* Jason Wang (jasow...@redhat.com) wrote:
>
> 在 2021/4/6 下午5:39, Dr. David Alan Gilbert 写道:
> > * Jason Wang (jasow...@redhat.com) wrote:
> > > Commit 4c70875372b8 ("pci: advertise a page aligned ATS") advertises
> > > the page aligned via ATS capability (RO) to unbrek recent Linux IOMMU
> > > drivers since 5.2. But it forgot the compat the capability which
> > > breaks the migration from old machine type:
> > >
> > > (qemu) qemu-kvm: get_pci_config_device: Bad config data: i=0x104 read:
> > > 0 device: 20 cmask: ff wmask: 0 w1cmask:0
> > >
> > > This patch introduces a new parameter "x-ats-page-aligned" for
> > > virtio-pci device and turns it on for machine type which is newer than
> > > 5.1.
> > I don't know the IOMMU code, but from the property/hw_compat I think
> > this is OK.
> > It's a bit tricky; since this was broken in 5.2, changing the
> > hw_compat_5_1 means that there are exisitng 5.2 users who will be broken
> > - howeer, the original 4c70875372b8 patch was sent to qemu-stable
> > which I think means there are other versions that are inconsistent as
> > well.
>
>
> Good point. It's not an easy task, we need to choose to break migration or
> virtio with vIOMMU.
>
> This patch chooes to do the latter, or is there any other better way to
> solve this?
Not that I can think of.
Dave
> Thanks
>
>
> >
> > Dave
> >
> > > Cc: Michael S. Tsirkin <m...@redhat.com>
> > > Cc: Peter Xu <pet...@redhat.com>
> > > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > > Cc: qemu-sta...@nongnu.org
> > > Fixes: 4c70875372b8 ("pci: advertise a page aligned ATS")
> > > Signed-off-by: Jason Wang <jasow...@redhat.com>
> > > ---
> > > Changes since V1:
> > > - switch to use "x-ats-page-aligned" instead
> > > ---
> > > hw/core/machine.c | 1 +
> > > hw/pci/pcie.c | 10 ++++++----
> > > hw/virtio/virtio-pci.c | 5 ++++-
> > > hw/virtio/virtio-pci.h | 5 +++++
> > > include/hw/pci/pcie.h | 2 +-
> > > 5 files changed, 17 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/hw/core/machine.c b/hw/core/machine.c
> > > index 9935c6ddd5..a50f2d5f0a 100644
> > > --- a/hw/core/machine.c
> > > +++ b/hw/core/machine.c
> > > @@ -53,6 +53,7 @@ GlobalProperty hw_compat_5_1[] = {
> > > { "nvme", "use-intel-id", "on"},
> > > { "pvpanic", "events", "1"}, /* PVPANIC_PANICKED */
> > > { "pl011", "migrate-clk", "off" },
> > > + { "virtio-pci", "x-ats-page-aligned", "off"},
> > > };
> > > const size_t hw_compat_5_1_len = G_N_ELEMENTS(hw_compat_5_1);
> > > diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> > > index a733e2fb87..fd0fa157e8 100644
> > > --- a/hw/pci/pcie.c
> > > +++ b/hw/pci/pcie.c
> > > @@ -963,16 +963,18 @@ void pcie_dev_ser_num_init(PCIDevice *dev, uint16_t
> > > offset, uint64_t ser_num)
> > > pci_set_quad(dev->config + offset + pci_dsn_cap, ser_num);
> > > }
> > > -void pcie_ats_init(PCIDevice *dev, uint16_t offset)
> > > +void pcie_ats_init(PCIDevice *dev, uint16_t offset, bool aligned)
> > > {
> > > pcie_add_capability(dev, PCI_EXT_CAP_ID_ATS, 0x1,
> > > offset, PCI_EXT_CAP_ATS_SIZEOF);
> > > dev->exp.ats_cap = offset;
> > > - /* Invalidate Queue Depth 0, Page Aligned Request 1 */
> > > - pci_set_word(dev->config + offset + PCI_ATS_CAP,
> > > - PCI_ATS_CAP_PAGE_ALIGNED);
> > > + /* Invalidate Queue Depth 0 */
> > > + if (aligned) {
> > > + pci_set_word(dev->config + offset + PCI_ATS_CAP,
> > > + PCI_ATS_CAP_PAGE_ALIGNED);
> > > + }
> > > /* STU 0, Disabled by default */
> > > pci_set_word(dev->config + offset + PCI_ATS_CTRL, 0);
> > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > > index 883045a223..2b7142a21e 100644
> > > --- a/hw/virtio/virtio-pci.c
> > > +++ b/hw/virtio/virtio-pci.c
> > > @@ -1848,7 +1848,8 @@ static void virtio_pci_realize(PCIDevice *pci_dev,
> > > Error **errp)
> > > }
> > > if (proxy->flags & VIRTIO_PCI_FLAG_ATS) {
> > > - pcie_ats_init(pci_dev, last_pcie_cap_offset);
> > > + pcie_ats_init(pci_dev, last_pcie_cap_offset,
> > > + proxy->flags &
> > > VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED);
> > > last_pcie_cap_offset += PCI_EXT_CAP_ATS_SIZEOF;
> > > }
> > > @@ -1925,6 +1926,8 @@ static Property virtio_pci_properties[] = {
> > > ignore_backend_features, false),
> > > DEFINE_PROP_BIT("ats", VirtIOPCIProxy, flags,
> > > VIRTIO_PCI_FLAG_ATS_BIT, false),
> > > + DEFINE_PROP_BIT("x-ats-page-aligned", VirtIOPCIProxy, flags,
> > > + VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT, true),
> > > DEFINE_PROP_BIT("x-pcie-deverr-init", VirtIOPCIProxy, flags,
> > > VIRTIO_PCI_FLAG_INIT_DEVERR_BIT, true),
> > > DEFINE_PROP_BIT("x-pcie-lnkctl-init", VirtIOPCIProxy, flags,
> > > diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
> > > index d7d5d403a9..2446dcd9ae 100644
> > > --- a/hw/virtio/virtio-pci.h
> > > +++ b/hw/virtio/virtio-pci.h
> > > @@ -42,6 +42,7 @@ enum {
> > > VIRTIO_PCI_FLAG_INIT_PM_BIT,
> > > VIRTIO_PCI_FLAG_INIT_FLR_BIT,
> > > VIRTIO_PCI_FLAG_AER_BIT,
> > > + VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT,
> > > };
> > > /* Need to activate work-arounds for buggy guests at vmstate load. */
> > > @@ -84,6 +85,10 @@ enum {
> > > /* Advanced Error Reporting capability */
> > > #define VIRTIO_PCI_FLAG_AER (1 << VIRTIO_PCI_FLAG_AER_BIT)
> > > +/* Page Aligned Address space Translation Service */
> > > +#define VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED \
> > > + (1 << VIRTIO_PCI_FLAG_ATS_PAGE_ALIGNED_BIT)
> > > +
> > > typedef struct {
> > > MSIMessage msg;
> > > int virq;
> > > diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
> > > index 14c58ebdb6..6063bee0ec 100644
> > > --- a/include/hw/pci/pcie.h
> > > +++ b/include/hw/pci/pcie.h
> > > @@ -137,7 +137,7 @@ void pcie_acs_reset(PCIDevice *dev);
> > > void pcie_ari_init(PCIDevice *dev, uint16_t offset, uint16_t nextfn);
> > > void pcie_dev_ser_num_init(PCIDevice *dev, uint16_t offset, uint64_t
> > > ser_num);
> > > -void pcie_ats_init(PCIDevice *dev, uint16_t offset);
> > > +void pcie_ats_init(PCIDevice *dev, uint16_t offset, bool aligned);
> > > void pcie_cap_slot_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState
> > > *dev,
> > > Error **errp);
> > > --
> > > 2.24.3 (Apple Git-128)
> > >
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
