Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

On Wed, 1 Aug 2018 23:28:53 +0530 Srinath Mannam wrote: > Hi Alex, > > In user space UIO driver (DPDK) implementation, sysfs interface > "/sys/devices/pci/.../resource0_wc" is used to map prefetchable PCI > resources as WC. > Platforms which support write-combining maps of PCI resources have > a

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

Hi Alex, In user space UIO driver (DPDK) implementation, sysfs interface "/sys/devices/pci/.../resource0_wc" is used to map prefetchable PCI resources as WC. Platforms which support write-combining maps of PCI resources have arch_can_pci_mmap_wc() flag enabled. So that it allows to map resources a

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

On Sat, Jul 21, 2018 at 1:57 AM, Alex Williamson wrote: > On Thu, 19 Jul 2018 21:49:48 +0530 > Srinath Mannam wrote: > >> HI Alex, >> >> On Thu, Jul 19, 2018 at 8:42 PM, Alex Williamson >> wrote: >> > On Thu, 19 Jul 2018 20:17:11 +0530 >> > Srinath Mannam wrote: >> > >> >> HI Alex, >> >> >> >>

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

On Thu, 19 Jul 2018 21:49:48 +0530 Srinath Mannam wrote: > HI Alex, > > On Thu, Jul 19, 2018 at 8:42 PM, Alex Williamson > wrote: > > On Thu, 19 Jul 2018 20:17:11 +0530 > > Srinath Mannam wrote: > > > >> HI Alex, > >> > >> On Thu, Jul 19, 2018 at 2:55 AM, Alex Williamson > >> wrote: > >>

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

HI Alex, On Thu, Jul 19, 2018 at 8:42 PM, Alex Williamson wrote: > On Thu, 19 Jul 2018 20:17:11 +0530 > Srinath Mannam wrote: > >> HI Alex, >> >> On Thu, Jul 19, 2018 at 2:55 AM, Alex Williamson >> wrote: >> > On Thu, 19 Jul 2018 00:05:18 +0530 >> > Srinath Mannam wrote: >> > >> >> Hi Alex, >>

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

On Thu, 19 Jul 2018 20:17:11 +0530 Srinath Mannam wrote: > HI Alex, > > On Thu, Jul 19, 2018 at 2:55 AM, Alex Williamson > wrote: > > On Thu, 19 Jul 2018 00:05:18 +0530 > > Srinath Mannam wrote: > > > >> Hi Alex, > >> > >> On Tue, Jul 17, 2018 at 8:52 PM, Alex Williamson > >> wrote: > >>

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

HI Alex, On Thu, Jul 19, 2018 at 2:55 AM, Alex Williamson wrote: > On Thu, 19 Jul 2018 00:05:18 +0530 > Srinath Mannam wrote: > >> Hi Alex, >> >> On Tue, Jul 17, 2018 at 8:52 PM, Alex Williamson >> wrote: >> > On Fri, 13 Jul 2018 10:26:17 +0530 >> > Srinath Mannam wrote: >> > >> >> By default

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

On Thu, 19 Jul 2018 00:05:18 +0530 Srinath Mannam wrote: > Hi Alex, > > On Tue, Jul 17, 2018 at 8:52 PM, Alex Williamson > wrote: > > On Fri, 13 Jul 2018 10:26:17 +0530 > > Srinath Mannam wrote: > > > >> By default all BARs map with VMA access permissions > >> as pgprot_noncached. > >> > >>

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

Hi Alex, On Tue, Jul 17, 2018 at 8:52 PM, Alex Williamson wrote: > On Fri, 13 Jul 2018 10:26:17 +0530 > Srinath Mannam wrote: > >> By default all BARs map with VMA access permissions >> as pgprot_noncached. >> >> In ARM64 pgprot_noncached is MT_DEVICE_nGnRnE which >> is strongly ordered and allo

Re: [RFC PATCH] vfio/pci: map prefetchble bars as writecombine

On Fri, 13 Jul 2018 10:26:17 +0530 Srinath Mannam wrote: > By default all BARs map with VMA access permissions > as pgprot_noncached. > > In ARM64 pgprot_noncached is MT_DEVICE_nGnRnE which > is strongly ordered and allows aligned access. > This type of mapping works for NON-PREFETCHABLE bars >

[RFC PATCH] vfio/pci: map prefetchble bars as writecombine

By default all BARs map with VMA access permissions as pgprot_noncached. In ARM64 pgprot_noncached is MT_DEVICE_nGnRnE which is strongly ordered and allows aligned access. This type of mapping works for NON-PREFETCHABLE bars containing EP controller registers. But it restricts PREFETCHABLE bars fr