| Message ID | 20231102155111.28821-2-guang.zeng@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: seftests: Support guest user mode execution and running | expand |
On Thu, Nov 02, 2023, Zeng Guang wrote: > Fix the approach to get page map from gva to gpa. > > If gva maps a 4-KByte page, current implementation of addr_arch_gva2gpa() > will obtain wrong page size and cannot derive correct offset from the guest > virtual address. > > Meanwhile using HUGEPAGE_MASK(x) to calculate the offset within page > (1G/2M/4K) mistakenly incorporates the upper part of 64-bit canonical > linear address. That will work out improper guest physical address if > translating guest virtual address in supervisor-mode address space. The "Meanwhile ..." is a huge clue that this should be two separate patches. > Signed-off-by: Zeng Guang <guang.zeng@intel.com> > --- > tools/testing/selftests/kvm/lib/x86_64/processor.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c > index d8288374078e..9f4b8c47edce 100644 > --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c > +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c > @@ -293,6 +293,7 @@ uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr, > if (vm_is_target_pte(pde, level, PG_LEVEL_2M)) > return pde; > > + *level = PG_LEVEL_4K; > return virt_get_pte(vm, pde, vaddr, PG_LEVEL_4K); > } > > @@ -496,7 +497,7 @@ vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva) > * No need for a hugepage mask on the PTE, x86-64 requires the "unused" > * address bits to be zero. > */ > - return PTE_GET_PA(*pte) | (gva & ~HUGEPAGE_MASK(level)); > + return PTE_GET_PA(*pte) | (gva & (HUGEPAGE_SIZE(level) - 1)); I think I would prefer to "fix" HUGEPAGE_MASK() and drop its incorporation of PHYSICAL_PAGE_MASK. Regardless of anyone's personal views on whether or not PAGE_MASK and HUGEPAGE_MASK should only cover physical address bits, (a) the _one_ usage of HUGEPAGE_MASK is broken and (b) diverging from the kernel for something like is a terrible idea, and the kernel does: #define PAGE_MASK (~(PAGE_SIZE-1)) #define HPAGE_MASK (~(HPAGE_SIZE - 1)) #define KVM_HPAGE_MASK(x) (~(KVM_HPAGE_SIZE(x) - 1)) Luckily, there are barely any users in x86, so I think the entirety of the conversion is this? diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 0f4792083d01..ef895038c87f 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -352,11 +352,12 @@ static inline unsigned int x86_model(unsigned int eax) #define PAGE_SHIFT 12 #define PAGE_SIZE (1ULL << PAGE_SHIFT) -#define PAGE_MASK (~(PAGE_SIZE-1) & PHYSICAL_PAGE_MASK) +#define PAGE_MASK (~(PAGE_SIZE-1)) +kvm_static_assert((PHYSICAL_PAGE_MASK & PAGE_MASK) == PHYSICAL_PAGE_MASK); #define HUGEPAGE_SHIFT(x) (PAGE_SHIFT + (((x) - 1) * 9)) #define HUGEPAGE_SIZE(x) (1UL << HUGEPAGE_SHIFT(x)) -#define HUGEPAGE_MASK(x) (~(HUGEPAGE_SIZE(x) - 1) & PHYSICAL_PAGE_MASK) +#define HUGEPAGE_MASK(x) (~(HUGEPAGE_SIZE(x) - 1)) #define PTE_GET_PA(pte) ((pte) & PHYSICAL_PAGE_MASK) #define PTE_GET_PFN(pte) (PTE_GET_PA(pte) >> PAGE_SHIFT) diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_tlb_flush.c b/tools/testing/selftests/kvm/x86_64/hyperv_tlb_flush.c index 05b56095cf76..cc5730322072 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_tlb_flush.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_tlb_flush.c @@ -623,7 +623,7 @@ int main(int argc, char *argv[]) for (i = 0; i < NTEST_PAGES; i++) { pte = vm_get_page_table_entry(vm, data->test_pages + i * PAGE_SIZE); gpa = addr_hva2gpa(vm, pte); - __virt_pg_map(vm, gva + PAGE_SIZE * i, gpa & PAGE_MASK, PG_LEVEL_4K); + __virt_pg_map(vm, gva + PAGE_SIZE * i, gpa & PHYSICAL_PAGE_MASK, PG_LEVEL_4K); data->test_pages_pte[i] = gva + (gpa & ~PAGE_MASK); }
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index d8288374078e..9f4b8c47edce 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -293,6 +293,7 @@ uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr, if (vm_is_target_pte(pde, level, PG_LEVEL_2M)) return pde; + *level = PG_LEVEL_4K; return virt_get_pte(vm, pde, vaddr, PG_LEVEL_4K); } @@ -496,7 +497,7 @@ vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva) * No need for a hugepage mask on the PTE, x86-64 requires the "unused" * address bits to be zero. */ - return PTE_GET_PA(*pte) | (gva & ~HUGEPAGE_MASK(level)); + return PTE_GET_PA(*pte) | (gva & (HUGEPAGE_SIZE(level) - 1)); } static void kvm_setup_gdt(struct kvm_vm *vm, struct kvm_dtable *dt)
Fix the approach to get page map from gva to gpa. If gva maps a 4-KByte page, current implementation of addr_arch_gva2gpa() will obtain wrong page size and cannot derive correct offset from the guest virtual address. Meanwhile using HUGEPAGE_MASK(x) to calculate the offset within page (1G/2M/4K) mistakenly incorporates the upper part of 64-bit canonical linear address. That will work out improper guest physical address if translating guest virtual address in supervisor-mode address space. Signed-off-by: Zeng Guang <guang.zeng@intel.com> --- tools/testing/selftests/kvm/lib/x86_64/processor.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)