* [PATCH 0/1] KVM support for VMD devices
@ 2020-04-22 17:14 Jon Derrick
2020-04-23 6:16 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Jon Derrick @ 2020-04-22 17:14 UTC (permalink / raw)
To: Bjorn Helgaas, qemu-devel
Cc: Lorenzo Pieralisi, linux-pci, virtualization, Andrzej Jakowski,
Jon Derrick
The two patches (Linux & QEMU) add support for passthrough VMD devices
in QEMU/KVM. VMD device 28C0 already supports passthrough natively by
providing the Host Physical Address in a shadow register to the guest
for correct bridge programming.
The QEMU patch emulates the 28C0 mode by creating a shadow register and
advertising its support by using QEMU's subsystem vendor/id.
The Linux patch matches the QEMU subsystem vendor/id to use the shadow
register.
Jon Derrick (1):
pci: vmd: Use Shadow MEMBAR registers for QEMU/KVM guests
drivers/pci/controller/vmd.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--
2.18.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 0/1] KVM support for VMD devices
2020-04-22 17:14 [PATCH 0/1] KVM support for VMD devices Jon Derrick
@ 2020-04-23 6:16 ` Christoph Hellwig
2020-04-23 15:18 ` Derrick, Jonathan
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2020-04-23 6:16 UTC (permalink / raw)
To: Jon Derrick
Cc: Bjorn Helgaas, qemu-devel, Lorenzo Pieralisi, linux-pci,
virtualization, Andrzej Jakowski
On Wed, Apr 22, 2020 at 01:14:44PM -0400, Jon Derrick wrote:
> The two patches (Linux & QEMU) add support for passthrough VMD devices
> in QEMU/KVM. VMD device 28C0 already supports passthrough natively by
> providing the Host Physical Address in a shadow register to the guest
> for correct bridge programming.
>
> The QEMU patch emulates the 28C0 mode by creating a shadow register and
> advertising its support by using QEMU's subsystem vendor/id.
> The Linux patch matches the QEMU subsystem vendor/id to use the shadow
> register.
Please pick a different PCI ID for Qemu vs real hardware so that we
can properly quirk them if they end up behaving differently due to
hardware or software bugs.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 0/1] KVM support for VMD devices
2020-04-23 6:16 ` Christoph Hellwig
@ 2020-04-23 15:18 ` Derrick, Jonathan
0 siblings, 0 replies; 3+ messages in thread
From: Derrick, Jonathan @ 2020-04-23 15:18 UTC (permalink / raw)
To: hch
Cc: lorenzo.pieralisi, linux-pci, helgaas, virtualization,
qemu-devel, Jakowski, Andrzej
On Wed, 2020-04-22 at 23:16 -0700, Christoph Hellwig wrote:
> On Wed, Apr 22, 2020 at 01:14:44PM -0400, Jon Derrick wrote:
> > The two patches (Linux & QEMU) add support for passthrough VMD devices
> > in QEMU/KVM. VMD device 28C0 already supports passthrough natively by
> > providing the Host Physical Address in a shadow register to the guest
> > for correct bridge programming.
> >
> > The QEMU patch emulates the 28C0 mode by creating a shadow register and
> > advertising its support by using QEMU's subsystem vendor/id.
> > The Linux patch matches the QEMU subsystem vendor/id to use the shadow
> > register.
>
> Please pick a different PCI ID for Qemu vs real hardware so that we
> can properly quirk them if they end up behaving differently due to
> hardware or software bugs.
Sure. Will look into that.
Thanks Christoph
Jon
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-04-22 17:14 [PATCH 0/1] KVM support for VMD devices Jon Derrick
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