Reviewed-by: Clement Mathieu--Drif <[email protected]>
On Wed, 2026-05-27 at 01:46 -0400, Zhenzhong Duan wrote:
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>
> The current code incorrectly uses "pasid != PCI_NO_PASID" to determine if
> PASID should be reported in fault records. However, this check happens
> after the code converts PCI_NO_PASID to PASID_0 in scalable mode.
>
> This means that for requests that originally had PCI_NO_PASID, the check
> "pasid != PCI_NO_PASID" will incorrectly return true (since pasid is now
> PASID_0), causing fault records to incorrectly indicate PASID validity.
> According to the VT-d specification, the PASID field in fault records is
> only valid for Requests-with-PASID:
>
> "When Set, indicates the faulted request has a PASID TLP Prefix."
>
> Fix this by capturing the original PASID state before the PCI_NO_PASID to
> PASID_0 conversion, ensuring fault records correctly reflect whether the
> original request had a PASID.
>
> Fixes: 1b2b12376c8a ("intel_iommu: process PASID-based iotlb invalidation")
> Suggested-by: Yi Liu <[[email protected]](mailto:[email protected])>
> Signed-off-by: Zhenzhong Duan
> <[[email protected]](mailto:[email protected])>
> ---
> hw/i386/intel_iommu.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 24d0211db7..034747b0b4 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -2109,6 +2109,7 @@ static bool vtd_do_iommu_translate(VTDAddressSpace
> *vtd_as, PCIBus *bus,
> bool is_fpd_set = false;
> bool reads = true;
> bool writes = true;
> + bool is_pasid = pasid != PCI_NO_PASID;
> uint8_t access_flags, pgtt;
> VTDIOTLBEntry *iotlb_entry;
> uint64_t xlat, size;
> @@ -2235,7 +2236,7 @@ static bool vtd_do_iommu_translate(VTDAddressSpace
> *vtd_as, PCIBus *bus,
> if (ret_fr) {
> if (!vtd_is_recoverable_fault(-ret_fr, iommu_idx)) {
> vtd_report_fault(s, -ret_fr, is_fpd_set, source_id,
> - addr, is_write, pasid != PCI_NO_PASID, pasid);
> + addr, is_write, is_pasid, pasid);
> }
> goto error;
> }
> --
> 2.47.3
>
