Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Michael S. Tsirkin]

On Thu, Feb 04, 2016 at 10:04:01AM +0800, Chen Fan wrote:
> 
> On 02/03/2016 09:57 PM, Michael S. Tsirkin wrote:
> >On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:
> >>On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:
> >>>On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:
> From: Chen Fan 
> 
> For now, for vfio pci passthough devices when qemu receives
> an error from host aer report, currentlly just terminate the guest,
> but usually user want to know what error occurred but stopping the
> guest, so this patches add aer capability support for vfio device,
> and pass the error to guest, and have guest driver to recover
> from the error.
> >>>I would like to see a version of this patchset that doesn't
> >>>depend on pci core changes.
> >>>I think that if you make this simplifying assumption:
> >>>
> >>>- all devices on same bus in guest are on same bus in host
> >>>
> >>>then you can handle both reset and hotplug simply in function 0
> >>>since it will belong to vfio.
> >>>
> >>>So we can have a version without pci core changes that simply assumes
> >>>this, and things will just work.
> >>>
> >>>
> >>>Now, if we wanted to enforce this limitation, I think the
> >>>cleanest way would be to add a callback in struct PCIDevice:
> >>>
> >>>   bool is_valid_function(PCIDevice *newfunction)
> >>>
> >>>and call it as each function is added.
> >>>This way aer function can validate that each function
> >>>added shares the same bus.
> >>>And this way issues will be detected directly and not when
> >>>function 0 is added.
> >>>
> >>>I would prefer this validation code to be a patch on top so we can merge
> >>>the functionality directly and avoid blocking it while we figure out the
> >>>best api to validate things.
> >>>
> >>>I don't see why making guest topology match host would
> >>>ever be a problem, but if it's required to support
> >>>configurations where these differ, I'd like to see
> >>>an attempt to address that be split out, after aer
> >>>is supported.
> >>Hi Michael,
> >>
> >>Just think about this more,  I think we also should check the vfio
> >>devices whether on the same bus at the time of function 0 is added.
> >>because we don't know the affected devices by a bus reset have
> >>already all been assigned to VM.
> >This is something vfio in kernel should check.
> >You can't rely on qemu being well behaved, so don't
> >even try to catch cases which would break host in userspace.
> >
> >qemu should only worry about not breaking guest.
> >
> >
> >>for example, the multi-function's hotplug.
> >>devices on same bus in host are added to VM one by one. when we
> >>test one device, we haven't yet added the other devices.
> >>so I think
> >>the patch should like below. then we could add a vfio_is_valid_function in
> >>vfio
> >>to test each device whether the affected devices on the same bus.
> >>
> >>Thanks,
> >>Chen
> >>
> >>diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> >>index d940f79..7163b56 100644
> >>--- a/hw/pci/pci.c
> >>+++ b/hw/pci/pci.c
> >>@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus, int bus_num,
> >>uint8_t devfn)
> >>  return bus->devices[devfn];
> >>  }
> >>
> >>+static int pci_bus_check_devices(PCIBus *bus)
> >>+{
> >>+PCIDeviceClass *pc;
> >>+int i, ret = 0;
> >>+
> >>+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
> >>+if (!bus->devices[i]) {
> >>+continue;
> >>+}
> >>+
> >>+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
> >>+if (!pc->is_valid_func) {
> >>+continue;
> >>+}
> >>+
> >>+ret = pc->is_valid_func(bus->devices[i], bus);
> >>+if (!ret) {
> >>+return -1;
> >>+}
> >>+}
> >>+return 0;
> >>+}
> >>+
> >>+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
> >>+{
> >>+if (pdev->bus == bus) {
> >>+return true;
> >>+}
> >>+
> >>+return false;
> >>+}
> >>+
> >I don't really understand what is this one doing.
> >Why do we need a default function?
> if the vfio driver in kernel can handle the bus reset for any one
> device in qemu without the affected devices assigned. I think
> we don't need this default one.
> BTW, IIRC at present the devices on the same bus in host can
> be assigned to different VM, so if we want to support this kind of
> bus reset for an independent device when enable aer, aren't we
> limiting the case that others devices on the same bus must be
> assigned to current VM?
> 
> Thanks,
> Chen

I don't believe this works at the moment, and
I'd expect kernel to prevent this,
so we should not rely on userspace code for this.
Alex, could you comment please?


> >>  static void pci_qdev_realize(DeviceState *qdev, Error **errp)
> >>  {
> >>  PCIDevice *pci_dev = (PCIDevice *)qdev;
> >>@@ -1878,6 +1910,14 @@ static void pci_qdev_realize(DeviceState *qdev, Error
> >>**errp)
> >>  pci_qdev_unrealize(DEVICE(pci_dev), NULL);
> >>  

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Michael S. Tsirkin]

On Thu, Feb 04, 2016 at 03:15:39PM -0500, Alex Williamson wrote:
> 
> 
> - Original Message -
> > On Thu, Feb 04, 2016 at 10:46:52AM -0700, Alex Williamson wrote:
> > > On Thu, 4 Feb 2016 13:21:57 +0200
> > > "Michael S. Tsirkin"  wrote:
> > > 
> > > > On Thu, Feb 04, 2016 at 10:04:01AM +0800, Chen Fan wrote:
> > > > > 
> > > > > On 02/03/2016 09:57 PM, Michael S. Tsirkin wrote:
> > > > > >On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:
> > > > > >>On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:
> > > > > >>>On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:
> > > > > From: Chen Fan 
> > > > > 
> > > > > For now, for vfio pci passthough devices when qemu receives
> > > > > an error from host aer report, currentlly just terminate the
> > > > > guest, but usually user want to know what error occurred but
> > > > > stopping the guest, so this patches add aer capability support
> > > > > for vfio device, and pass the error to guest, and have guest
> > > > > driver to recover from the error.
> > > > > >>>I would like to see a version of this patchset that doesn't
> > > > > >>>depend on pci core changes.
> > > > > >>>I think that if you make this simplifying assumption:
> > > > > >>>
> > > > > >>>- all devices on same bus in guest are on same bus in host
> > > > > >>>
> > > > > >>>then you can handle both reset and hotplug simply in function 0
> > > > > >>>since it will belong to vfio.
> > > > > >>>
> > > > > >>>So we can have a version without pci core changes that simply
> > > > > >>>assumes this, and things will just work.
> > > > > >>>
> > > > > >>>
> > > > > >>>Now, if we wanted to enforce this limitation, I think the
> > > > > >>>cleanest way would be to add a callback in struct PCIDevice:
> > > > > >>>
> > > > > >>>   bool is_valid_function(PCIDevice *newfunction)
> > > > > >>>
> > > > > >>>and call it as each function is added.
> > > > > >>>This way aer function can validate that each function
> > > > > >>>added shares the same bus.
> > > > > >>>And this way issues will be detected directly and not when
> > > > > >>>function 0 is added.
> > > > > >>>
> > > > > >>>I would prefer this validation code to be a patch on top so we
> > > > > >>>can merge the functionality directly and avoid blocking it while
> > > > > >>>we figure out the best api to validate things.
> > > > > >>>
> > > > > >>>I don't see why making guest topology match host would
> > > > > >>>ever be a problem, but if it's required to support
> > > > > >>>configurations where these differ, I'd like to see
> > > > > >>>an attempt to address that be split out, after aer
> > > > > >>>is supported.
> > > > > >>Hi Michael,
> > > > > >>
> > > > > >>Just think about this more,  I think we also should check the vfio
> > > > > >>devices whether on the same bus at the time of function 0 is
> > > > > >>added. because we don't know the affected devices by a bus reset
> > > > > >>have already all been assigned to VM.
> > > > > >This is something vfio in kernel should check.
> > > > > >You can't rely on qemu being well behaved, so don't
> > > > > >even try to catch cases which would break host in userspace.
> > > > > >
> > > > > >qemu should only worry about not breaking guest.
> > > > > >
> > > > > >  
> > > > > >>for example, the multi-function's hotplug.
> > > > > >>devices on same bus in host are added to VM one by one. when we
> > > > > >>test one device, we haven't yet added the other devices.
> > > > > >>so I think
> > > > > >>the patch should like below. then we could add a
> > > > > >>vfio_is_valid_function in vfio
> > > > > >>to test each device whether the affected devices on the same bus.
> > > > > >>
> > > > > >>Thanks,
> > > > > >>Chen
> > > > > >>
> > > > > >>diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > > > > >>index d940f79..7163b56 100644
> > > > > >>--- a/hw/pci/pci.c
> > > > > >>+++ b/hw/pci/pci.c
> > > > > >>@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus,
> > > > > >>int bus_num, uint8_t devfn)
> > > > > >>  return bus->devices[devfn];
> > > > > >>  }
> > > > > >>
> > > > > >>+static int pci_bus_check_devices(PCIBus *bus)
> > > > > >>+{
> > > > > >>+PCIDeviceClass *pc;
> > > > > >>+int i, ret = 0;
> > > > > >>+
> > > > > >>+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
> > > > > >>+if (!bus->devices[i]) {
> > > > > >>+continue;
> > > > > >>+}
> > > > > >>+
> > > > > >>+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
> > > > > >>+if (!pc->is_valid_func) {
> > > > > >>+continue;
> > > > > >>+}
> > > > > >>+
> > > > > >>+ret = pc->is_valid_func(bus->devices[i], bus);
> > > > > >>+if (!ret) {
> > > > > >>+return -1;
> > > > > >>+}
> > > > > >>+}
> > > > > >>+return 0;
> > > > > >>+}
> > > > > >>+
> > > > > >>+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
> > > > > >>+{
> > > > > >>+   

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Alex Williamson]

On Thu, 4 Feb 2016 13:21:57 +0200
"Michael S. Tsirkin"  wrote:

> On Thu, Feb 04, 2016 at 10:04:01AM +0800, Chen Fan wrote:
> > 
> > On 02/03/2016 09:57 PM, Michael S. Tsirkin wrote:  
> > >On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:  
> > >>On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:  
> > >>>On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:  
> > From: Chen Fan 
> > 
> > For now, for vfio pci passthough devices when qemu receives
> > an error from host aer report, currentlly just terminate the
> > guest, but usually user want to know what error occurred but
> > stopping the guest, so this patches add aer capability support
> > for vfio device, and pass the error to guest, and have guest
> > driver to recover from the error.  
> > >>>I would like to see a version of this patchset that doesn't
> > >>>depend on pci core changes.
> > >>>I think that if you make this simplifying assumption:
> > >>>
> > >>>- all devices on same bus in guest are on same bus in host
> > >>>
> > >>>then you can handle both reset and hotplug simply in function 0
> > >>>since it will belong to vfio.
> > >>>
> > >>>So we can have a version without pci core changes that simply
> > >>>assumes this, and things will just work.
> > >>>
> > >>>
> > >>>Now, if we wanted to enforce this limitation, I think the
> > >>>cleanest way would be to add a callback in struct PCIDevice:
> > >>>
> > >>> bool is_valid_function(PCIDevice *newfunction)
> > >>>
> > >>>and call it as each function is added.
> > >>>This way aer function can validate that each function
> > >>>added shares the same bus.
> > >>>And this way issues will be detected directly and not when
> > >>>function 0 is added.
> > >>>
> > >>>I would prefer this validation code to be a patch on top so we
> > >>>can merge the functionality directly and avoid blocking it while
> > >>>we figure out the best api to validate things.
> > >>>
> > >>>I don't see why making guest topology match host would
> > >>>ever be a problem, but if it's required to support
> > >>>configurations where these differ, I'd like to see
> > >>>an attempt to address that be split out, after aer
> > >>>is supported.  
> > >>Hi Michael,
> > >>
> > >>Just think about this more,  I think we also should check the vfio
> > >>devices whether on the same bus at the time of function 0 is
> > >>added. because we don't know the affected devices by a bus reset
> > >>have already all been assigned to VM.  
> > >This is something vfio in kernel should check.
> > >You can't rely on qemu being well behaved, so don't
> > >even try to catch cases which would break host in userspace.
> > >
> > >qemu should only worry about not breaking guest.
> > >
> > >  
> > >>for example, the multi-function's hotplug.
> > >>devices on same bus in host are added to VM one by one. when we
> > >>test one device, we haven't yet added the other devices.
> > >>so I think
> > >>the patch should like below. then we could add a
> > >>vfio_is_valid_function in vfio
> > >>to test each device whether the affected devices on the same bus.
> > >>
> > >>Thanks,
> > >>Chen
> > >>
> > >>diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > >>index d940f79..7163b56 100644
> > >>--- a/hw/pci/pci.c
> > >>+++ b/hw/pci/pci.c
> > >>@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus,
> > >>int bus_num, uint8_t devfn)
> > >>  return bus->devices[devfn];
> > >>  }
> > >>
> > >>+static int pci_bus_check_devices(PCIBus *bus)
> > >>+{
> > >>+PCIDeviceClass *pc;
> > >>+int i, ret = 0;
> > >>+
> > >>+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
> > >>+if (!bus->devices[i]) {
> > >>+continue;
> > >>+}
> > >>+
> > >>+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
> > >>+if (!pc->is_valid_func) {
> > >>+continue;
> > >>+}
> > >>+
> > >>+ret = pc->is_valid_func(bus->devices[i], bus);
> > >>+if (!ret) {
> > >>+return -1;
> > >>+}
> > >>+}
> > >>+return 0;
> > >>+}
> > >>+
> > >>+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
> > >>+{
> > >>+if (pdev->bus == bus) {
> > >>+return true;
> > >>+}
> > >>+
> > >>+return false;
> > >>+}
> > >>+  
> > >I don't really understand what is this one doing.
> > >Why do we need a default function?  
> > if the vfio driver in kernel can handle the bus reset for any one
> > device in qemu without the affected devices assigned. I think
> > we don't need this default one.
> > BTW, IIRC at present the devices on the same bus in host can
> > be assigned to different VM, so if we want to support this kind of
> > bus reset for an independent device when enable aer, aren't we
> > limiting the case that others devices on the same bus must be
> > assigned to current VM?
> > 
> > Thanks,
> > Chen  
> 
> I don't believe this works at the moment, and
> I'd expect kernel to prevent this,
> so we 

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Michael S. Tsirkin]

On Thu, Feb 04, 2016 at 10:46:52AM -0700, Alex Williamson wrote:
> On Thu, 4 Feb 2016 13:21:57 +0200
> "Michael S. Tsirkin"  wrote:
> 
> > On Thu, Feb 04, 2016 at 10:04:01AM +0800, Chen Fan wrote:
> > > 
> > > On 02/03/2016 09:57 PM, Michael S. Tsirkin wrote:  
> > > >On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:  
> > > >>On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:  
> > > >>>On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:  
> > > From: Chen Fan 
> > > 
> > > For now, for vfio pci passthough devices when qemu receives
> > > an error from host aer report, currentlly just terminate the
> > > guest, but usually user want to know what error occurred but
> > > stopping the guest, so this patches add aer capability support
> > > for vfio device, and pass the error to guest, and have guest
> > > driver to recover from the error.  
> > > >>>I would like to see a version of this patchset that doesn't
> > > >>>depend on pci core changes.
> > > >>>I think that if you make this simplifying assumption:
> > > >>>
> > > >>>- all devices on same bus in guest are on same bus in host
> > > >>>
> > > >>>then you can handle both reset and hotplug simply in function 0
> > > >>>since it will belong to vfio.
> > > >>>
> > > >>>So we can have a version without pci core changes that simply
> > > >>>assumes this, and things will just work.
> > > >>>
> > > >>>
> > > >>>Now, if we wanted to enforce this limitation, I think the
> > > >>>cleanest way would be to add a callback in struct PCIDevice:
> > > >>>
> > > >>>   bool is_valid_function(PCIDevice *newfunction)
> > > >>>
> > > >>>and call it as each function is added.
> > > >>>This way aer function can validate that each function
> > > >>>added shares the same bus.
> > > >>>And this way issues will be detected directly and not when
> > > >>>function 0 is added.
> > > >>>
> > > >>>I would prefer this validation code to be a patch on top so we
> > > >>>can merge the functionality directly and avoid blocking it while
> > > >>>we figure out the best api to validate things.
> > > >>>
> > > >>>I don't see why making guest topology match host would
> > > >>>ever be a problem, but if it's required to support
> > > >>>configurations where these differ, I'd like to see
> > > >>>an attempt to address that be split out, after aer
> > > >>>is supported.  
> > > >>Hi Michael,
> > > >>
> > > >>Just think about this more,  I think we also should check the vfio
> > > >>devices whether on the same bus at the time of function 0 is
> > > >>added. because we don't know the affected devices by a bus reset
> > > >>have already all been assigned to VM.  
> > > >This is something vfio in kernel should check.
> > > >You can't rely on qemu being well behaved, so don't
> > > >even try to catch cases which would break host in userspace.
> > > >
> > > >qemu should only worry about not breaking guest.
> > > >
> > > >  
> > > >>for example, the multi-function's hotplug.
> > > >>devices on same bus in host are added to VM one by one. when we
> > > >>test one device, we haven't yet added the other devices.
> > > >>so I think
> > > >>the patch should like below. then we could add a
> > > >>vfio_is_valid_function in vfio
> > > >>to test each device whether the affected devices on the same bus.
> > > >>
> > > >>Thanks,
> > > >>Chen
> > > >>
> > > >>diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > > >>index d940f79..7163b56 100644
> > > >>--- a/hw/pci/pci.c
> > > >>+++ b/hw/pci/pci.c
> > > >>@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus,
> > > >>int bus_num, uint8_t devfn)
> > > >>  return bus->devices[devfn];
> > > >>  }
> > > >>
> > > >>+static int pci_bus_check_devices(PCIBus *bus)
> > > >>+{
> > > >>+PCIDeviceClass *pc;
> > > >>+int i, ret = 0;
> > > >>+
> > > >>+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
> > > >>+if (!bus->devices[i]) {
> > > >>+continue;
> > > >>+}
> > > >>+
> > > >>+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
> > > >>+if (!pc->is_valid_func) {
> > > >>+continue;
> > > >>+}
> > > >>+
> > > >>+ret = pc->is_valid_func(bus->devices[i], bus);
> > > >>+if (!ret) {
> > > >>+return -1;
> > > >>+}
> > > >>+}
> > > >>+return 0;
> > > >>+}
> > > >>+
> > > >>+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
> > > >>+{
> > > >>+if (pdev->bus == bus) {
> > > >>+return true;
> > > >>+}
> > > >>+
> > > >>+return false;
> > > >>+}
> > > >>+  
> > > >I don't really understand what is this one doing.
> > > >Why do we need a default function?  
> > > if the vfio driver in kernel can handle the bus reset for any one
> > > device in qemu without the affected devices assigned. I think
> > > we don't need this default one.
> > > BTW, IIRC at present the devices on the same bus in host can
> > > be assigned to different VM, so if we 

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Alex Williamson]

- Original Message -
> On Thu, Feb 04, 2016 at 10:46:52AM -0700, Alex Williamson wrote:
> > On Thu, 4 Feb 2016 13:21:57 +0200
> > "Michael S. Tsirkin"  wrote:
> > 
> > > On Thu, Feb 04, 2016 at 10:04:01AM +0800, Chen Fan wrote:
> > > > 
> > > > On 02/03/2016 09:57 PM, Michael S. Tsirkin wrote:
> > > > >On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:
> > > > >>On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:
> > > > >>>On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:
> > > > From: Chen Fan 
> > > > 
> > > > For now, for vfio pci passthough devices when qemu receives
> > > > an error from host aer report, currentlly just terminate the
> > > > guest, but usually user want to know what error occurred but
> > > > stopping the guest, so this patches add aer capability support
> > > > for vfio device, and pass the error to guest, and have guest
> > > > driver to recover from the error.
> > > > >>>I would like to see a version of this patchset that doesn't
> > > > >>>depend on pci core changes.
> > > > >>>I think that if you make this simplifying assumption:
> > > > >>>
> > > > >>>- all devices on same bus in guest are on same bus in host
> > > > >>>
> > > > >>>then you can handle both reset and hotplug simply in function 0
> > > > >>>since it will belong to vfio.
> > > > >>>
> > > > >>>So we can have a version without pci core changes that simply
> > > > >>>assumes this, and things will just work.
> > > > >>>
> > > > >>>
> > > > >>>Now, if we wanted to enforce this limitation, I think the
> > > > >>>cleanest way would be to add a callback in struct PCIDevice:
> > > > >>>
> > > > >>> bool is_valid_function(PCIDevice *newfunction)
> > > > >>>
> > > > >>>and call it as each function is added.
> > > > >>>This way aer function can validate that each function
> > > > >>>added shares the same bus.
> > > > >>>And this way issues will be detected directly and not when
> > > > >>>function 0 is added.
> > > > >>>
> > > > >>>I would prefer this validation code to be a patch on top so we
> > > > >>>can merge the functionality directly and avoid blocking it while
> > > > >>>we figure out the best api to validate things.
> > > > >>>
> > > > >>>I don't see why making guest topology match host would
> > > > >>>ever be a problem, but if it's required to support
> > > > >>>configurations where these differ, I'd like to see
> > > > >>>an attempt to address that be split out, after aer
> > > > >>>is supported.
> > > > >>Hi Michael,
> > > > >>
> > > > >>Just think about this more,  I think we also should check the vfio
> > > > >>devices whether on the same bus at the time of function 0 is
> > > > >>added. because we don't know the affected devices by a bus reset
> > > > >>have already all been assigned to VM.
> > > > >This is something vfio in kernel should check.
> > > > >You can't rely on qemu being well behaved, so don't
> > > > >even try to catch cases which would break host in userspace.
> > > > >
> > > > >qemu should only worry about not breaking guest.
> > > > >
> > > > >  
> > > > >>for example, the multi-function's hotplug.
> > > > >>devices on same bus in host are added to VM one by one. when we
> > > > >>test one device, we haven't yet added the other devices.
> > > > >>so I think
> > > > >>the patch should like below. then we could add a
> > > > >>vfio_is_valid_function in vfio
> > > > >>to test each device whether the affected devices on the same bus.
> > > > >>
> > > > >>Thanks,
> > > > >>Chen
> > > > >>
> > > > >>diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > > > >>index d940f79..7163b56 100644
> > > > >>--- a/hw/pci/pci.c
> > > > >>+++ b/hw/pci/pci.c
> > > > >>@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus,
> > > > >>int bus_num, uint8_t devfn)
> > > > >>  return bus->devices[devfn];
> > > > >>  }
> > > > >>
> > > > >>+static int pci_bus_check_devices(PCIBus *bus)
> > > > >>+{
> > > > >>+PCIDeviceClass *pc;
> > > > >>+int i, ret = 0;
> > > > >>+
> > > > >>+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
> > > > >>+if (!bus->devices[i]) {
> > > > >>+continue;
> > > > >>+}
> > > > >>+
> > > > >>+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
> > > > >>+if (!pc->is_valid_func) {
> > > > >>+continue;
> > > > >>+}
> > > > >>+
> > > > >>+ret = pc->is_valid_func(bus->devices[i], bus);
> > > > >>+if (!ret) {
> > > > >>+return -1;
> > > > >>+}
> > > > >>+}
> > > > >>+return 0;
> > > > >>+}
> > > > >>+
> > > > >>+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
> > > > >>+{
> > > > >>+if (pdev->bus == bus) {
> > > > >>+return true;
> > > > >>+}
> > > > >>+
> > > > >>+return false;
> > > > >>+}
> > > > >>+
> > > > >I don't really understand what is this one doing.
> > > > >Why do we need a default function?
> > > > if the vfio driver in kernel can 

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Chen Fan]

On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:

On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:

From: Chen Fan 

For now, for vfio pci passthough devices when qemu receives
an error from host aer report, currentlly just terminate the guest,
but usually user want to know what error occurred but stopping the
guest, so this patches add aer capability support for vfio device,
and pass the error to guest, and have guest driver to recover
from the error.

I would like to see a version of this patchset that doesn't
depend on pci core changes.
I think that if you make this simplifying assumption:

- all devices on same bus in guest are on same bus in host

then you can handle both reset and hotplug simply in function 0
since it will belong to vfio.

So we can have a version without pci core changes that simply assumes
this, and things will just work.


Now, if we wanted to enforce this limitation, I think the
cleanest way would be to add a callback in struct PCIDevice:

bool is_valid_function(PCIDevice *newfunction)

and call it as each function is added.
This way aer function can validate that each function
added shares the same bus.
And this way issues will be detected directly and not when
function 0 is added.

I would prefer this validation code to be a patch on top so we can merge
the functionality directly and avoid blocking it while we figure out the
best api to validate things.

I don't see why making guest topology match host would
ever be a problem, but if it's required to support
configurations where these differ, I'd like to see
an attempt to address that be split out, after aer
is supported.

Hi Michael,

Just think about this more,  I think we also should check the vfio
devices whether on the same bus at the time of function 0 is added.
because we don't know the affected devices by a bus reset have
already all been assigned to VM. for example, the multi-function's hotplug.
devices on same bus in host are added to VM one by one. when we
test one device, we haven't yet added the other devices. so I think
the patch should like below. then we could add a vfio_is_valid_function 
in vfio

to test each device whether the affected devices on the same bus.

Thanks,
Chen

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index d940f79..7163b56 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus, int 
bus_num, uint8_t devfn)

 return bus->devices[devfn];
 }

+static int pci_bus_check_devices(PCIBus *bus)
+{
+PCIDeviceClass *pc;
+int i, ret = 0;
+
+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
+if (!bus->devices[i]) {
+continue;
+}
+
+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
+if (!pc->is_valid_func) {
+continue;
+}
+
+ret = pc->is_valid_func(bus->devices[i], bus);
+if (!ret) {
+return -1;
+}
+}
+return 0;
+}
+
+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
+{
+if (pdev->bus == bus) {
+return true;
+}
+
+return false;
+}
+
 static void pci_qdev_realize(DeviceState *qdev, Error **errp)
 {
 PCIDevice *pci_dev = (PCIDevice *)qdev;
@@ -1878,6 +1910,14 @@ static void pci_qdev_realize(DeviceState *qdev, 
Error **errp)

 pci_qdev_unrealize(DEVICE(pci_dev), NULL);
 return;
 }
+
+if (DEVICE(pci_dev)->hotplugged &&
+pci_get_function_0(pci_dev) == pci_dev &&
+pci_bus_check_devices(bus)) {
+error_setg(errp, "failed to hotplug function 0");
+pci_qdev_unrealize(DEVICE(pci_dev), NULL);
+return;
+}
 }

 static void pci_default_realize(PCIDevice *dev, Error **errp)
@@ -2390,6 +2430,7 @@ static void pci_device_class_init(ObjectClass 
*klass, void *data)

 k->bus_type = TYPE_PCI_BUS;
 k->props = pci_props;
 pc->realize = pci_default_realize;
+pc->is_valid_func = pci_is_valid_function;
 }

 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index dedf277..a89580f 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -191,6 +191,7 @@ typedef struct PCIDeviceClass {

 void (*realize)(PCIDevice *dev, Error **errp);
 int (*init)(PCIDevice *dev);/* TODO convert to realize() and remove */
+bool (*is_valid_func)(PCIDevice *dev, PCIBus *bus);
 PCIUnregisterFunc *exit;
 PCIConfigReadFunc *config_read;
 PCIConfigWriteFunc *config_write;








v15-v16:
10/14, 11/14 are new to introduce a reset sequence id to specify the
vfio devices has been reset for that reset. other patches aren't modified.

v14-v15:
1. add device hot reset callback
2. add bus_in_reset for vfio device to avoid multi do host bus reset

v13-v14:
1. for multifunction device, requiring all functions enable AER.(9/13)
2. due to all affected functions receive error signal, ignore no
   error occurred 

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Michael S. Tsirkin]

On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:
> 
> On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:
> >On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:
> >>From: Chen Fan 
> >>
> >>For now, for vfio pci passthough devices when qemu receives
> >>an error from host aer report, currentlly just terminate the guest,
> >>but usually user want to know what error occurred but stopping the
> >>guest, so this patches add aer capability support for vfio device,
> >>and pass the error to guest, and have guest driver to recover
> >>from the error.
> >I would like to see a version of this patchset that doesn't
> >depend on pci core changes.
> >I think that if you make this simplifying assumption:
> >
> >- all devices on same bus in guest are on same bus in host
> >
> >then you can handle both reset and hotplug simply in function 0
> >since it will belong to vfio.
> >
> >So we can have a version without pci core changes that simply assumes
> >this, and things will just work.
> >
> >
> >Now, if we wanted to enforce this limitation, I think the
> >cleanest way would be to add a callback in struct PCIDevice:
> >
> > bool is_valid_function(PCIDevice *newfunction)
> >
> >and call it as each function is added.
> >This way aer function can validate that each function
> >added shares the same bus.
> >And this way issues will be detected directly and not when
> >function 0 is added.
> >
> >I would prefer this validation code to be a patch on top so we can merge
> >the functionality directly and avoid blocking it while we figure out the
> >best api to validate things.
> >
> >I don't see why making guest topology match host would
> >ever be a problem, but if it's required to support
> >configurations where these differ, I'd like to see
> >an attempt to address that be split out, after aer
> >is supported.
> Hi Michael,
> 
> Just think about this more,  I think we also should check the vfio
> devices whether on the same bus at the time of function 0 is added.
> because we don't know the affected devices by a bus reset have
> already all been assigned to VM.

This is something vfio in kernel should check.
You can't rely on qemu being well behaved, so don't
even try to catch cases which would break host in userspace.

qemu should only worry about not breaking guest.


> for example, the multi-function's hotplug.
> devices on same bus in host are added to VM one by one. when we
> test one device, we haven't yet added the other devices.
> so I think
> the patch should like below. then we could add a vfio_is_valid_function in
> vfio
> to test each device whether the affected devices on the same bus.
> 
> Thanks,
> Chen
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index d940f79..7163b56 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus, int bus_num,
> uint8_t devfn)
>  return bus->devices[devfn];
>  }
> 
> +static int pci_bus_check_devices(PCIBus *bus)
> +{
> +PCIDeviceClass *pc;
> +int i, ret = 0;
> +
> +for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
> +if (!bus->devices[i]) {
> +continue;
> +}
> +
> +pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
> +if (!pc->is_valid_func) {
> +continue;
> +}
> +
> +ret = pc->is_valid_func(bus->devices[i], bus);
> +if (!ret) {
> +return -1;
> +}
> +}
> +return 0;
> +}
> +
> +static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
> +{
> +if (pdev->bus == bus) {
> +return true;
> +}
> +
> +return false;
> +}
> +

I don't really understand what is this one doing.
Why do we need a default function?

>  static void pci_qdev_realize(DeviceState *qdev, Error **errp)
>  {
>  PCIDevice *pci_dev = (PCIDevice *)qdev;
> @@ -1878,6 +1910,14 @@ static void pci_qdev_realize(DeviceState *qdev, Error
> **errp)
>  pci_qdev_unrealize(DEVICE(pci_dev), NULL);
>  return;
>  }
> +
> +if (DEVICE(pci_dev)->hotplugged &&
> +pci_get_function_0(pci_dev) == pci_dev &&
> +pci_bus_check_devices(bus)) {
> +error_setg(errp, "failed to hotplug function 0");
> +pci_qdev_unrealize(DEVICE(pci_dev), NULL);
> +return;
> +}
>  }
> 
>  static void pci_default_realize(PCIDevice *dev, Error **errp)
> @@ -2390,6 +2430,7 @@ static void pci_device_class_init(ObjectClass *klass,
> void *data)
>  k->bus_type = TYPE_PCI_BUS;
>  k->props = pci_props;
>  pc->realize = pci_default_realize;
> +pc->is_valid_func = pci_is_valid_function;
>  }
> 
>  AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index dedf277..a89580f 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -191,6 +191,7 @@ typedef struct PCIDeviceClass {
> 
>  void (*realize)(PCIDevice *dev, Error **errp);
>  int (*init)(PCIDevice *dev);/* 

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Chen Fan]

On 02/03/2016 09:57 PM, Michael S. Tsirkin wrote:

On Wed, Feb 03, 2016 at 04:54:01PM +0800, Chen Fan wrote:

On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:

On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:

From: Chen Fan 

For now, for vfio pci passthough devices when qemu receives
an error from host aer report, currentlly just terminate the guest,
but usually user want to know what error occurred but stopping the
guest, so this patches add aer capability support for vfio device,
and pass the error to guest, and have guest driver to recover

>from the error.
I would like to see a version of this patchset that doesn't
depend on pci core changes.
I think that if you make this simplifying assumption:

- all devices on same bus in guest are on same bus in host

then you can handle both reset and hotplug simply in function 0
since it will belong to vfio.

So we can have a version without pci core changes that simply assumes
this, and things will just work.


Now, if we wanted to enforce this limitation, I think the
cleanest way would be to add a callback in struct PCIDevice:

bool is_valid_function(PCIDevice *newfunction)

and call it as each function is added.
This way aer function can validate that each function
added shares the same bus.
And this way issues will be detected directly and not when
function 0 is added.

I would prefer this validation code to be a patch on top so we can merge
the functionality directly and avoid blocking it while we figure out the
best api to validate things.

I don't see why making guest topology match host would
ever be a problem, but if it's required to support
configurations where these differ, I'd like to see
an attempt to address that be split out, after aer
is supported.

Hi Michael,

Just think about this more,  I think we also should check the vfio
devices whether on the same bus at the time of function 0 is added.
because we don't know the affected devices by a bus reset have
already all been assigned to VM.

This is something vfio in kernel should check.
You can't rely on qemu being well behaved, so don't
even try to catch cases which would break host in userspace.

qemu should only worry about not breaking guest.



for example, the multi-function's hotplug.
devices on same bus in host are added to VM one by one. when we
test one device, we haven't yet added the other devices.
so I think
the patch should like below. then we could add a vfio_is_valid_function in
vfio
to test each device whether the affected devices on the same bus.

Thanks,
Chen

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index d940f79..7163b56 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -1836,6 +1836,38 @@ PCIDevice *pci_find_device(PCIBus *bus, int bus_num,
uint8_t devfn)
  return bus->devices[devfn];
  }

+static int pci_bus_check_devices(PCIBus *bus)
+{
+PCIDeviceClass *pc;
+int i, ret = 0;
+
+for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
+if (!bus->devices[i]) {
+continue;
+}
+
+pc = PCI_DEVICE_GET_CLASS(bus->devices[i]);
+if (!pc->is_valid_func) {
+continue;
+}
+
+ret = pc->is_valid_func(bus->devices[i], bus);
+if (!ret) {
+return -1;
+}
+}
+return 0;
+}
+
+static bool pci_is_valid_function(PCIDevice *pdev, PCIBus *bus)
+{
+if (pdev->bus == bus) {
+return true;
+}
+
+return false;
+}
+

I don't really understand what is this one doing.
Why do we need a default function?

if the vfio driver in kernel can handle the bus reset for any one
device in qemu without the affected devices assigned. I think
we don't need this default one.
BTW, IIRC at present the devices on the same bus in host can
be assigned to different VM, so if we want to support this kind of
bus reset for an independent device when enable aer, aren't we
limiting the case that others devices on the same bus must be
assigned to current VM?

Thanks,
Chen

  static void pci_qdev_realize(DeviceState *qdev, Error **errp)
  {
  PCIDevice *pci_dev = (PCIDevice *)qdev;
@@ -1878,6 +1910,14 @@ static void pci_qdev_realize(DeviceState *qdev, Error
**errp)
  pci_qdev_unrealize(DEVICE(pci_dev), NULL);
  return;
  }
+
+if (DEVICE(pci_dev)->hotplugged &&
+pci_get_function_0(pci_dev) == pci_dev &&
+pci_bus_check_devices(bus)) {
+error_setg(errp, "failed to hotplug function 0");
+pci_qdev_unrealize(DEVICE(pci_dev), NULL);
+return;
+}
  }

  static void pci_default_realize(PCIDevice *dev, Error **errp)
@@ -2390,6 +2430,7 @@ static void pci_device_class_init(ObjectClass *klass,
void *data)
  k->bus_type = TYPE_PCI_BUS;
  k->props = pci_props;
  pc->realize = pci_default_realize;
+pc->is_valid_func = pci_is_valid_function;
  }

  AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index dedf277..a89580f 

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Chen Fan]

On 01/17/2016 02:34 AM, Michael S. Tsirkin wrote:

On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:

From: Chen Fan 

For now, for vfio pci passthough devices when qemu receives
an error from host aer report, currentlly just terminate the guest,
but usually user want to know what error occurred but stopping the
guest, so this patches add aer capability support for vfio device,
and pass the error to guest, and have guest driver to recover
from the error.

I would like to see a version of this patchset that doesn't
depend on pci core changes.
I think that if you make this simplifying assumption:

- all devices on same bus in guest are on same bus in host

then you can handle both reset and hotplug simply in function 0
since it will belong to vfio.

So we can have a version without pci core changes that simply assumes
this, and things will just work.


Now, if we wanted to enforce this limitation, I think the
cleanest way would be to add a callback in struct PCIDevice:

bool is_valid_function(PCIDevice *newfunction)

and call it as each function is added.
This way aer function can validate that each function
added shares the same bus.
And this way issues will be detected directly and not when
function 0 is added.

I would prefer this validation code to be a patch on top so we can merge
the functionality directly and avoid blocking it while we figure out the
best api to validate things.

I don't see why making guest topology match host would
ever be a problem, but if it's required to support
configurations where these differ, I'd like to see
an attempt to address that be split out, after aer
is supported.

Hi Michael,

   it's a good idea. we should simplify the implementation of the aer 
function first

without more affect on pci core code.

Thanks,
Chen





v15-v16:
10/14, 11/14 are new to introduce a reset sequence id to specify the
vfio devices has been reset for that reset. other patches aren't modified.

v14-v15:
1. add device hot reset callback
2. add bus_in_reset for vfio device to avoid multi do host bus reset

v13-v14:
1. for multifunction device, requiring all functions enable AER.(9/13)
2. due to all affected functions receive error signal, ignore no
   error occurred function. (12/13)

v12-v13:
1. since support multifuncion hotplug, here add callback to enable aer.
2. add pci device pre+post reset for aer host reset.

Chen Fan (14):
   vfio: extract vfio_get_hot_reset_info as a single function
   vfio: squeeze out vfio_pci_do_hot_reset for support bus reset
   pcie: modify the capability size assert
   vfio: make the 4 bytes aligned for capability size
   vfio: add pcie extanded capability support
   aer: impove pcie_aer_init to support vfio device
   vfio: add aer support for vfio device
   vfio: add check host bus reset is support or not
   add check reset mechanism when hotplug vfio device
   pci: introduce pci bus pre reset
   vfio: introduce last reset sequence id
   pcie_aer: expose pcie_aer_msg() interface
   vfio-pci: pass the aer error to guest
   vfio: add 'aer' property to expose aercap

  hw/pci-bridge/ioh3420.c|   2 +-
  hw/pci-bridge/xio3130_downstream.c |   2 +-
  hw/pci-bridge/xio3130_upstream.c   |   2 +-
  hw/pci/pci.c   |  42 +++
  hw/pci/pci_bridge.c|   3 +
  hw/pci/pcie.c  |   2 +-
  hw/pci/pcie_aer.c  |   6 +-
  hw/vfio/pci.c  | 616 +
  hw/vfio/pci.h  |   9 +
  include/hw/pci/pci.h   |   1 +
  include/hw/pci/pci_bus.h   |   8 +
  include/hw/pci/pcie_aer.h  |   3 +-
  12 files changed, 624 insertions(+), 72 deletions(-)

--
1.9.3




.

Re: [Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Michael S. Tsirkin]

On Tue, Jan 12, 2016 at 10:43:01AM +0800, Cao jin wrote:
> From: Chen Fan 
> 
> For now, for vfio pci passthough devices when qemu receives
> an error from host aer report, currentlly just terminate the guest,
> but usually user want to know what error occurred but stopping the
> guest, so this patches add aer capability support for vfio device,
> and pass the error to guest, and have guest driver to recover
> from the error.

I would like to see a version of this patchset that doesn't
depend on pci core changes.
I think that if you make this simplifying assumption:

- all devices on same bus in guest are on same bus in host

then you can handle both reset and hotplug simply in function 0
since it will belong to vfio.

So we can have a version without pci core changes that simply assumes
this, and things will just work.


Now, if we wanted to enforce this limitation, I think the
cleanest way would be to add a callback in struct PCIDevice:

bool is_valid_function(PCIDevice *newfunction)

and call it as each function is added.
This way aer function can validate that each function
added shares the same bus.
And this way issues will be detected directly and not when
function 0 is added.

I would prefer this validation code to be a patch on top so we can merge
the functionality directly and avoid blocking it while we figure out the
best api to validate things.

I don't see why making guest topology match host would
ever be a problem, but if it's required to support
configurations where these differ, I'd like to see
an attempt to address that be split out, after aer
is supported.



> v15-v16:
>10/14, 11/14 are new to introduce a reset sequence id to specify the
>vfio devices has been reset for that reset. other patches aren't modified.
> 
> v14-v15:
>1. add device hot reset callback
>2. add bus_in_reset for vfio device to avoid multi do host bus reset
> 
> v13-v14:
>1. for multifunction device, requiring all functions enable AER.(9/13)
>2. due to all affected functions receive error signal, ignore no
>   error occurred function. (12/13)
> 
> v12-v13:
>1. since support multifuncion hotplug, here add callback to enable aer.
>2. add pci device pre+post reset for aer host reset.
> 
> Chen Fan (14):
>   vfio: extract vfio_get_hot_reset_info as a single function
>   vfio: squeeze out vfio_pci_do_hot_reset for support bus reset
>   pcie: modify the capability size assert
>   vfio: make the 4 bytes aligned for capability size
>   vfio: add pcie extanded capability support
>   aer: impove pcie_aer_init to support vfio device
>   vfio: add aer support for vfio device
>   vfio: add check host bus reset is support or not
>   add check reset mechanism when hotplug vfio device
>   pci: introduce pci bus pre reset
>   vfio: introduce last reset sequence id
>   pcie_aer: expose pcie_aer_msg() interface
>   vfio-pci: pass the aer error to guest
>   vfio: add 'aer' property to expose aercap
> 
>  hw/pci-bridge/ioh3420.c|   2 +-
>  hw/pci-bridge/xio3130_downstream.c |   2 +-
>  hw/pci-bridge/xio3130_upstream.c   |   2 +-
>  hw/pci/pci.c   |  42 +++
>  hw/pci/pci_bridge.c|   3 +
>  hw/pci/pcie.c  |   2 +-
>  hw/pci/pcie_aer.c  |   6 +-
>  hw/vfio/pci.c  | 616 
> +
>  hw/vfio/pci.h  |   9 +
>  include/hw/pci/pci.h   |   1 +
>  include/hw/pci/pci_bus.h   |   8 +
>  include/hw/pci/pcie_aer.h  |   3 +-
>  12 files changed, 624 insertions(+), 72 deletions(-)
> 
> -- 
> 1.9.3
> 
> 

[Qemu-devel] [PATCH v16 00/14] vfio-pci: pass the aer error to guest

[Cao jin]

From: Chen Fan 

For now, for vfio pci passthough devices when qemu receives
an error from host aer report, currentlly just terminate the guest,
but usually user want to know what error occurred but stopping the
guest, so this patches add aer capability support for vfio device,
and pass the error to guest, and have guest driver to recover
from the error.

v15-v16:
   10/14, 11/14 are new to introduce a reset sequence id to specify the
   vfio devices has been reset for that reset. other patches aren't modified.

v14-v15:
   1. add device hot reset callback
   2. add bus_in_reset for vfio device to avoid multi do host bus reset

v13-v14:
   1. for multifunction device, requiring all functions enable AER.(9/13)
   2. due to all affected functions receive error signal, ignore no
  error occurred function. (12/13)

v12-v13:
   1. since support multifuncion hotplug, here add callback to enable aer.
   2. add pci device pre+post reset for aer host reset.

Chen Fan (14):
  vfio: extract vfio_get_hot_reset_info as a single function
  vfio: squeeze out vfio_pci_do_hot_reset for support bus reset
  pcie: modify the capability size assert
  vfio: make the 4 bytes aligned for capability size
  vfio: add pcie extanded capability support
  aer: impove pcie_aer_init to support vfio device
  vfio: add aer support for vfio device
  vfio: add check host bus reset is support or not
  add check reset mechanism when hotplug vfio device
  pci: introduce pci bus pre reset
  vfio: introduce last reset sequence id
  pcie_aer: expose pcie_aer_msg() interface
  vfio-pci: pass the aer error to guest
  vfio: add 'aer' property to expose aercap

 hw/pci-bridge/ioh3420.c|   2 +-
 hw/pci-bridge/xio3130_downstream.c |   2 +-
 hw/pci-bridge/xio3130_upstream.c   |   2 +-
 hw/pci/pci.c   |  42 +++
 hw/pci/pci_bridge.c|   3 +
 hw/pci/pcie.c  |   2 +-
 hw/pci/pcie_aer.c  |   6 +-
 hw/vfio/pci.c  | 616 +
 hw/vfio/pci.h  |   9 +
 include/hw/pci/pci.h   |   1 +
 include/hw/pci/pci_bus.h   |   8 +
 include/hw/pci/pcie_aer.h  |   3 +-
 12 files changed, 624 insertions(+), 72 deletions(-)

-- 
1.9.3