From 82b28deb25f37e8422b14493a2efa2852638206d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Date: Mon, 19 Jun 2023 15:46:03 +0200 Subject: [PATCH] iommu/vtd: fix address translation for leaf entries MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix two issues related to leaf address lookups in VT-d: * When translating an address that falls inside of a superpage in the IOMMU page tables the fetching of the PTE value wasn't masking of the contiguous related data, which caused the returned data to be corrupt as it would contain bits that the caller would interpret as part of the address. * When the requested leaf address wasn't mapped by a superpage the returned value wouldn't have any of the low 12 bits set, thus missing the permission bits expected by the caller. Take the opportunity to also adjust the function comment to note that when returning the full PTE the bits above PADDR_BITS are removed. Fixes: c71e55501a61 ('VT-d: have callers specify the target level for page table walks') Signed-off-by: Roger Pau Monné Reviewed-by: Jan Beulich Reviewed-by: Kevin Tian --- xen/drivers/passthrough/vtd/iommu.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c index 130a159cde..0e3062c820 100644 --- a/xen/drivers/passthrough/vtd/iommu.c +++ b/xen/drivers/passthrough/vtd/iommu.c @@ -310,7 +310,7 @@ static u64 bus_to_context_maddr(struct vtd_iommu *iommu, u8 bus) * failure, * - for target > 0 the physical address of the page table holding the leaf * PTE for the requested address, - * - for target == 0 the full PTE. + * - for target == 0 the full PTE contents below PADDR_BITS limit. */ static uint64_t addr_to_dma_page_maddr(struct domain *domain, daddr_t addr, unsigned int target, @@ -368,7 +368,7 @@ static uint64_t addr_to_dma_page_maddr(struct domain *domain, daddr_t addr, * with the address adjusted to account for the residual of * the walk. */ - pte_maddr = pte->val + + pte_maddr = (pte->val & PADDR_MASK) + (addr & ((1UL << level_to_offset_bits(level)) - 1) & PAGE_MASK); if ( !target ) @@ -413,7 +413,11 @@ static uint64_t addr_to_dma_page_maddr(struct domain *domain, daddr_t addr, } if ( --level == target ) + { + if ( !target ) + pte_maddr = pte->val & PADDR_MASK; break; + } unmap_vtd_domain_page(parent); parent = map_vtd_domain_page(pte_maddr);