Messages in this thread | | | Subject | Re: [PATCH 5.4 v2 1/1] iommu/vt-d: Fix agaw for a supported 48 bit guest address width | From | Lu Baolu <> | Date | Mon, 12 Apr 2021 07:49:20 +0800 |
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I guess you need to ask Greg KH <gregkh@linuxfoundation.org> with this Cc-ing to stable@vger.kernel.org.
Best regards, baolu
On 2021/4/12 3:36, Saeed Mirzamohammadi wrote: > Hi Lu, > > Thanks for the review. May I know when do we expect this to be applied > to 5.4? > > Thanks, > Saeed > >> On Apr 7, 2021, at 5:25 PM, Lu Baolu <baolu.lu@linux.intel.com >> <mailto:baolu.lu@linux.intel.com>> wrote: >> >> On 4/8/21 2:40 AM, Saeed Mirzamohammadi wrote: >>> The IOMMU driver calculates the guest addressability for a DMA request >>> based on the value of the mgaw reported from the IOMMU. However, this >>> is a fused value and as mentioned in the spec, the guest width >>> should be calculated based on the minimum of supported adjusted guest >>> address width (SAGAW) and MGAW. >>> This is from specification: >>> "Guest addressability for a given DMA request is limited to the >>> minimum of the value reported through this field and the adjusted >>> guest address width of the corresponding page-table structure. >>> (Adjusted guest address widths supported by hardware are reported >>> through the SAGAW field)." >>> This causes domain initialization to fail and following >>> errors appear for EHCI PCI driver: >>> [ 2.486393] ehci-pci 0000:01:00.4: EHCI Host Controller >>> [ 2.486624] ehci-pci 0000:01:00.4: new USB bus registered, >>> assigned bus >>> number 1 >>> [ 2.489127] ehci-pci 0000:01:00.4: DMAR: Allocating domain failed >>> [ 2.489350] ehci-pci 0000:01:00.4: DMAR: 32bit DMA uses non-identity >>> mapping >>> [ 2.489359] ehci-pci 0000:01:00.4: can't setup: -12 >>> [ 2.489531] ehci-pci 0000:01:00.4: USB bus 1 deregistered >>> [ 2.490023] ehci-pci 0000:01:00.4: init 0000:01:00.4 fail, -12 >>> [ 2.490358] ehci-pci: probe of 0000:01:00.4 failed with error -12 >>> This issue happens when the value of the sagaw corresponds to a >>> 48-bit agaw. This fix updates the calculation of the agaw based on >>> the minimum of IOMMU's sagaw value and MGAW. >>> Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com >>> <mailto:saeed.mirzamohammadi@oracle.com>> >>> Tested-by: Camille Lu <camille.lu@hpe.com <mailto:camille.lu@hpe.com>> >>> --- >>> Change in v2: >>> - Added cap_width to calculate AGAW based on the minimum value of >>> MGAW and AGAW. >>> --- >>> drivers/iommu/intel-iommu.c | 7 ++++--- >>> 1 file changed, 4 insertions(+), 3 deletions(-) >>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c >>> index 953d86ca6d2b..a2a03df97704 100644 >>> --- a/drivers/iommu/intel-iommu.c >>> +++ b/drivers/iommu/intel-iommu.c >>> @@ -1853,7 +1853,7 @@ static inline int guestwidth_to_adjustwidth(int >>> gaw) >>> static int domain_init(struct dmar_domain *domain, struct >>> intel_iommu *iommu, >>> int guest_width) >>> { >>> -int adjust_width, agaw; >>> +int adjust_width, agaw, cap_width; >>> unsigned long sagaw; >>> int err; >>> @@ -1867,8 +1867,9 @@ static int domain_init(struct dmar_domain >>> *domain, struct intel_iommu *iommu, >>> domain_reserve_special_ranges(domain); >>> /* calculate AGAW */ >>> -if (guest_width > cap_mgaw(iommu->cap)) >>> -guest_width = cap_mgaw(iommu->cap); >>> +cap_width = min_t(int, cap_mgaw(iommu->cap), >>> agaw_to_width(iommu->agaw)); >>> +if (guest_width > cap_width) >>> +guest_width = cap_width; >>> domain->gaw = guest_width; >>> adjust_width = guestwidth_to_adjustwidth(guest_width); >>> agaw = width_to_agaw(adjust_width); >> >> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com >> <mailto:baolu.lu@linux.intel.com>> >> >> Best regards, >> baolu >
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