Re: [QEMU PATCH v6 1/1] virtio-pci: implement No_Soft_Reset bit
On 2024/3/18 16:04, Michael S. Tsirkin wrote:
> On Thu, Feb 22, 2024 at 11:40:10AM +0800, Jiqian Chen wrote:
>> In current code, when guest does S3, virtio devices are reset due to
>> the bit No_Soft_Reset is not set. After resetting, the display resources
>> of virtio-gpu are destroyed, then the display can't come back and only
>> show blank after resuming.
>>
>> Implement No_Soft_Reset bit of PCI_PM_CTRL register, then guest can check
>> this bit, if this bit is set, the devices resetting will not be done, and
>> then the display can work after resuming.
>>
>> Signed-off-by: Jiqian Chen
>> ---
>> hw/virtio/virtio-pci.c | 37 +-
>> include/hw/virtio/virtio-pci.h | 5 +
>> 2 files changed, 41 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
>> index 1a7039fb0c68..da5312010345 100644
>> --- a/hw/virtio/virtio-pci.c
>> +++ b/hw/virtio/virtio-pci.c
>> @@ -2197,6 +2197,11 @@ static void virtio_pci_realize(PCIDevice *pci_dev,
>> Error **errp)
>> pcie_cap_lnkctl_init(pci_dev);
>> }
>>
>> +if (proxy->flags & VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET) {
>> +pci_set_word(pci_dev->config + pos + PCI_PM_CTRL,
>> + PCI_PM_CTRL_NO_SOFT_RESET);
>> +}
>> +
>> if (proxy->flags & VIRTIO_PCI_FLAG_INIT_PM) {
>> /* Init Power Management Control Register */
>> pci_set_word(pci_dev->wmask + pos + PCI_PM_CTRL,
>
>
> Don't we need compat machinery to avoid breaking migration for
> existing machine types?
Could you elaborate on it? I am sorry I don't know which machine types to be
compatible with, and how to be compatible with them.
Can I simply set the default value of x-pcie-pm-no-soft-reset to false? If
someone need this bit, they can set x-pcie-pm-no-soft-reset=true in the config
parameters for Qemu. So that will not affect exiting machine types?
>
>> @@ -2259,18 +2264,46 @@ static void virtio_pci_reset(DeviceState *qdev)
>> }
>> }
>>
>> +static bool device_no_need_reset(PCIDevice *dev)
>> +{
>> +if (pci_is_express(dev)) {
>> +uint16_t pmcsr;
>> +
>> +pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
>> +/*
>> + * When No_Soft_Reset bit is set and device
>
> the device
Will change in next version.
>
>> + * is in D3hot state, can't reset device
>
> can't? or don't?
Will change to "don't" in next version.
>
>> + */
>> +if ((pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) &&
>> +(pmcsr & PCI_PM_CTRL_STATE_MASK) == 3)
>> +return true;
>
> coding style violation
Will add braces {} in next version.
>
>> +}
>> +
>> +return false;
>> +}
>> +
>> static void virtio_pci_bus_reset_hold(Object *obj)
>> {
>> PCIDevice *dev = PCI_DEVICE(obj);
>> DeviceState *qdev = DEVICE(obj);
>>
>> +if (device_no_need_reset(dev))
>> +return;
>> +
>> virtio_pci_reset(qdev);
>>
>> if (pci_is_express(dev)) {
>> +uint16_t pmcsr;
>> +uint16_t val = 0;
>> +
>> pcie_cap_deverr_reset(dev);
>> pcie_cap_lnkctl_reset(dev);
>>
>> -pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, 0);
>> +/* don't reset the RO bits */
>> +pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
>> +val = val | (pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) |
>> +(pmcsr & PCI_PM_CTRL_DATA_SCALE_MASK);
>> +pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, val);
>
> First, we have test and clear for this.
>
> Second, this has to be conditional on the flag, no?
Before resetting, I first read the value of config, its function is equivalent
to checking the label, right?
If the flag is set, the value of No_Soft_Reset is 1, the bit of "val" is also 1.
If the flag is not set, the value of No_Soft_Reset is 0, "val" is also 0.
> Without the flag don't we reset everything?
We need reset everything include the RO bit, right?
If so, that is my fault, then I will change to check the flag of proxy in next
version.
> Or you can reuse wmask for this, also an option.
>
> Also what's going on with PCI_PM_CTRL_DATA_SCALE_MASK?
> Where does that come from?
I read from PCI spec, the bit DATA_SCALE and No_Soft_Reset are both RO bit, so
I thought we shouldn't reset them.
It is something wrong with my understanding, I will remove
PCI_PM_CTRL_DATA_SCALE_MASK in next version. Sorry.
>
>> }
>> }
>>
>> @@ -2297,6 +2330,8 @@ static Property virtio_pci_properties[] = {
>> VIRTIO_PCI_FLAG_INIT_LNKCTL_BIT, true),
>> DEFINE_PROP_BIT("x-pcie-pm-init", VirtIOPCIProxy, flags,
>> VIRTIO_PCI_FLAG_INIT_PM_BIT, true),
>> +DEFINE_PROP_BIT("x-pcie-pm-no-soft-reset", VirtIOPCIProxy, flags,
>> +VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT, true),
>> DEFINE_PROP_BIT("x-pcie-flr-init",
Re: [QEMU PATCH v6 1/1] virtio-pci: implement No_Soft_Reset bit
On Thu, Feb 22, 2024 at 11:40:10AM +0800, Jiqian Chen wrote:
> In current code, when guest does S3, virtio devices are reset due to
> the bit No_Soft_Reset is not set. After resetting, the display resources
> of virtio-gpu are destroyed, then the display can't come back and only
> show blank after resuming.
>
> Implement No_Soft_Reset bit of PCI_PM_CTRL register, then guest can check
> this bit, if this bit is set, the devices resetting will not be done, and
> then the display can work after resuming.
>
> Signed-off-by: Jiqian Chen
> ---
> hw/virtio/virtio-pci.c | 37 +-
> include/hw/virtio/virtio-pci.h | 5 +
> 2 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 1a7039fb0c68..da5312010345 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -2197,6 +2197,11 @@ static void virtio_pci_realize(PCIDevice *pci_dev,
> Error **errp)
> pcie_cap_lnkctl_init(pci_dev);
> }
>
> +if (proxy->flags & VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET) {
> +pci_set_word(pci_dev->config + pos + PCI_PM_CTRL,
> + PCI_PM_CTRL_NO_SOFT_RESET);
> +}
> +
> if (proxy->flags & VIRTIO_PCI_FLAG_INIT_PM) {
> /* Init Power Management Control Register */
> pci_set_word(pci_dev->wmask + pos + PCI_PM_CTRL,
Don't we need compat machinery to avoid breaking migration for
existing machine types?
> @@ -2259,18 +2264,46 @@ static void virtio_pci_reset(DeviceState *qdev)
> }
> }
>
> +static bool device_no_need_reset(PCIDevice *dev)
> +{
> +if (pci_is_express(dev)) {
> +uint16_t pmcsr;
> +
> +pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
> +/*
> + * When No_Soft_Reset bit is set and device
the device
> + * is in D3hot state, can't reset device
can't? or don't?
> + */
> +if ((pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) &&
> +(pmcsr & PCI_PM_CTRL_STATE_MASK) == 3)
> +return true;
coding style violation
> +}
> +
> +return false;
> +}
> +
> static void virtio_pci_bus_reset_hold(Object *obj)
> {
> PCIDevice *dev = PCI_DEVICE(obj);
> DeviceState *qdev = DEVICE(obj);
>
> +if (device_no_need_reset(dev))
> +return;
> +
> virtio_pci_reset(qdev);
>
> if (pci_is_express(dev)) {
> +uint16_t pmcsr;
> +uint16_t val = 0;
> +
> pcie_cap_deverr_reset(dev);
> pcie_cap_lnkctl_reset(dev);
>
> -pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, 0);
> +/* don't reset the RO bits */
> +pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
> +val = val | (pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) |
> +(pmcsr & PCI_PM_CTRL_DATA_SCALE_MASK);
> +pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, val);
First, we have test and clear for this.
Second, this has to be conditional on the flag, no?
Without the flag don't we reset everything?
Or you can reuse wmask for this, also an option.
Also what's going on with PCI_PM_CTRL_DATA_SCALE_MASK?
Where does that come from?
> }
> }
>
> @@ -2297,6 +2330,8 @@ static Property virtio_pci_properties[] = {
> VIRTIO_PCI_FLAG_INIT_LNKCTL_BIT, true),
> DEFINE_PROP_BIT("x-pcie-pm-init", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_INIT_PM_BIT, true),
> +DEFINE_PROP_BIT("x-pcie-pm-no-soft-reset", VirtIOPCIProxy, flags,
> +VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT, true),
> DEFINE_PROP_BIT("x-pcie-flr-init", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
> DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
> diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
> index 59d88018c16a..9e67ba38c748 100644
> --- a/include/hw/virtio/virtio-pci.h
> +++ b/include/hw/virtio/virtio-pci.h
> @@ -43,6 +43,7 @@ enum {
> VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> VIRTIO_PCI_FLAG_AER_BIT,
> VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> +VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT,
> };
>
> /* Need to activate work-arounds for buggy guests at vmstate load. */
> @@ -79,6 +80,10 @@ enum {
> /* Init Power Management */
> #define VIRTIO_PCI_FLAG_INIT_PM (1 << VIRTIO_PCI_FLAG_INIT_PM_BIT)
>
> +/* Init The No_Soft_Reset bit of Power Management */
> +#define VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET \
> + (1 << VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT)
> +
> /* Init Function Level Reset capability */
> #define VIRTIO_PCI_FLAG_INIT_FLR (1 << VIRTIO_PCI_FLAG_INIT_FLR_BIT)
>
> --
> 2.34.1
Re: [QEMU PATCH v6 1/1] virtio-pci: implement No_Soft_Reset bit
Hi Michael S. Tsirkin,
Do you have any comments on this patch?
On 2024/2/22 11:40, Jiqian Chen wrote:
> In current code, when guest does S3, virtio devices are reset due to
> the bit No_Soft_Reset is not set. After resetting, the display resources
> of virtio-gpu are destroyed, then the display can't come back and only
> show blank after resuming.
>
> Implement No_Soft_Reset bit of PCI_PM_CTRL register, then guest can check
> this bit, if this bit is set, the devices resetting will not be done, and
> then the display can work after resuming.
>
> Signed-off-by: Jiqian Chen
> ---
> hw/virtio/virtio-pci.c | 37 +-
> include/hw/virtio/virtio-pci.h | 5 +
> 2 files changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index 1a7039fb0c68..da5312010345 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -2197,6 +2197,11 @@ static void virtio_pci_realize(PCIDevice *pci_dev,
> Error **errp)
> pcie_cap_lnkctl_init(pci_dev);
> }
>
> +if (proxy->flags & VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET) {
> +pci_set_word(pci_dev->config + pos + PCI_PM_CTRL,
> + PCI_PM_CTRL_NO_SOFT_RESET);
> +}
> +
> if (proxy->flags & VIRTIO_PCI_FLAG_INIT_PM) {
> /* Init Power Management Control Register */
> pci_set_word(pci_dev->wmask + pos + PCI_PM_CTRL,
> @@ -2259,18 +2264,46 @@ static void virtio_pci_reset(DeviceState *qdev)
> }
> }
>
> +static bool device_no_need_reset(PCIDevice *dev)
> +{
> +if (pci_is_express(dev)) {
> +uint16_t pmcsr;
> +
> +pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
> +/*
> + * When No_Soft_Reset bit is set and device
> + * is in D3hot state, can't reset device
> + */
> +if ((pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) &&
> +(pmcsr & PCI_PM_CTRL_STATE_MASK) == 3)
> +return true;
> +}
> +
> +return false;
> +}
> +
> static void virtio_pci_bus_reset_hold(Object *obj)
> {
> PCIDevice *dev = PCI_DEVICE(obj);
> DeviceState *qdev = DEVICE(obj);
>
> +if (device_no_need_reset(dev))
> +return;
> +
> virtio_pci_reset(qdev);
>
> if (pci_is_express(dev)) {
> +uint16_t pmcsr;
> +uint16_t val = 0;
> +
> pcie_cap_deverr_reset(dev);
> pcie_cap_lnkctl_reset(dev);
>
> -pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, 0);
> +/* don't reset the RO bits */
> +pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
> +val = val | (pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) |
> +(pmcsr & PCI_PM_CTRL_DATA_SCALE_MASK);
> +pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, val);
> }
> }
>
> @@ -2297,6 +2330,8 @@ static Property virtio_pci_properties[] = {
> VIRTIO_PCI_FLAG_INIT_LNKCTL_BIT, true),
> DEFINE_PROP_BIT("x-pcie-pm-init", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_INIT_PM_BIT, true),
> +DEFINE_PROP_BIT("x-pcie-pm-no-soft-reset", VirtIOPCIProxy, flags,
> +VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT, true),
> DEFINE_PROP_BIT("x-pcie-flr-init", VirtIOPCIProxy, flags,
> VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
> DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
> diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
> index 59d88018c16a..9e67ba38c748 100644
> --- a/include/hw/virtio/virtio-pci.h
> +++ b/include/hw/virtio/virtio-pci.h
> @@ -43,6 +43,7 @@ enum {
> VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> VIRTIO_PCI_FLAG_AER_BIT,
> VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> +VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT,
> };
>
> /* Need to activate work-arounds for buggy guests at vmstate load. */
> @@ -79,6 +80,10 @@ enum {
> /* Init Power Management */
> #define VIRTIO_PCI_FLAG_INIT_PM (1 << VIRTIO_PCI_FLAG_INIT_PM_BIT)
>
> +/* Init The No_Soft_Reset bit of Power Management */
> +#define VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET \
> + (1 << VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT)
> +
> /* Init Function Level Reset capability */
> #define VIRTIO_PCI_FLAG_INIT_FLR (1 << VIRTIO_PCI_FLAG_INIT_FLR_BIT)
>
--
Best regards,
Jiqian Chen.
[QEMU PATCH v6 1/1] virtio-pci: implement No_Soft_Reset bit
In current code, when guest does S3, virtio devices are reset due to
the bit No_Soft_Reset is not set. After resetting, the display resources
of virtio-gpu are destroyed, then the display can't come back and only
show blank after resuming.
Implement No_Soft_Reset bit of PCI_PM_CTRL register, then guest can check
this bit, if this bit is set, the devices resetting will not be done, and
then the display can work after resuming.
Signed-off-by: Jiqian Chen
---
hw/virtio/virtio-pci.c | 37 +-
include/hw/virtio/virtio-pci.h | 5 +
2 files changed, 41 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 1a7039fb0c68..da5312010345 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -2197,6 +2197,11 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error
**errp)
pcie_cap_lnkctl_init(pci_dev);
}
+if (proxy->flags & VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET) {
+pci_set_word(pci_dev->config + pos + PCI_PM_CTRL,
+ PCI_PM_CTRL_NO_SOFT_RESET);
+}
+
if (proxy->flags & VIRTIO_PCI_FLAG_INIT_PM) {
/* Init Power Management Control Register */
pci_set_word(pci_dev->wmask + pos + PCI_PM_CTRL,
@@ -2259,18 +2264,46 @@ static void virtio_pci_reset(DeviceState *qdev)
}
}
+static bool device_no_need_reset(PCIDevice *dev)
+{
+if (pci_is_express(dev)) {
+uint16_t pmcsr;
+
+pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
+/*
+ * When No_Soft_Reset bit is set and device
+ * is in D3hot state, can't reset device
+ */
+if ((pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) &&
+(pmcsr & PCI_PM_CTRL_STATE_MASK) == 3)
+return true;
+}
+
+return false;
+}
+
static void virtio_pci_bus_reset_hold(Object *obj)
{
PCIDevice *dev = PCI_DEVICE(obj);
DeviceState *qdev = DEVICE(obj);
+if (device_no_need_reset(dev))
+return;
+
virtio_pci_reset(qdev);
if (pci_is_express(dev)) {
+uint16_t pmcsr;
+uint16_t val = 0;
+
pcie_cap_deverr_reset(dev);
pcie_cap_lnkctl_reset(dev);
-pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, 0);
+/* don't reset the RO bits */
+pmcsr = pci_get_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL);
+val = val | (pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) |
+(pmcsr & PCI_PM_CTRL_DATA_SCALE_MASK);
+pci_set_word(dev->config + dev->exp.pm_cap + PCI_PM_CTRL, val);
}
}
@@ -2297,6 +2330,8 @@ static Property virtio_pci_properties[] = {
VIRTIO_PCI_FLAG_INIT_LNKCTL_BIT, true),
DEFINE_PROP_BIT("x-pcie-pm-init", VirtIOPCIProxy, flags,
VIRTIO_PCI_FLAG_INIT_PM_BIT, true),
+DEFINE_PROP_BIT("x-pcie-pm-no-soft-reset", VirtIOPCIProxy, flags,
+VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT, true),
DEFINE_PROP_BIT("x-pcie-flr-init", VirtIOPCIProxy, flags,
VIRTIO_PCI_FLAG_INIT_FLR_BIT, true),
DEFINE_PROP_BIT("aer", VirtIOPCIProxy, flags,
diff --git a/include/hw/virtio/virtio-pci.h b/include/hw/virtio/virtio-pci.h
index 59d88018c16a..9e67ba38c748 100644
--- a/include/hw/virtio/virtio-pci.h
+++ b/include/hw/virtio/virtio-pci.h
@@ -43,6 +43,7 @@ enum {
VIRTIO_PCI_FLAG_INIT_FLR_BIT,
VIRTIO_PCI_FLAG_AER_BIT,
VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
+VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT,
};
/* Need to activate work-arounds for buggy guests at vmstate load. */
@@ -79,6 +80,10 @@ enum {
/* Init Power Management */
#define VIRTIO_PCI_FLAG_INIT_PM (1 << VIRTIO_PCI_FLAG_INIT_PM_BIT)
+/* Init The No_Soft_Reset bit of Power Management */
+#define VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET \
+ (1 << VIRTIO_PCI_FLAG_PM_NO_SOFT_RESET_BIT)
+
/* Init Function Level Reset capability */
#define VIRTIO_PCI_FLAG_INIT_FLR (1 << VIRTIO_PCI_FLAG_INIT_FLR_BIT)
--
2.34.1
