github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-30 10:04:04 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

KVM: selftests: Drop reserved bit checks from PTE accessor

Browse Source 
Drop the reserved bit checks from the helper to retrieve a PTE, there's
very little value in sanity checking the constructed page tables as any
will quickly be noticed in the form of an unexpected #PF.  The checks
also place unnecessary restrictions on the usage of the helpers, e.g. if
a test _wanted_ to set reserved bits for whatever reason.

Removing the NX check in particular allows for the removal of the @vcpu
param, which will in turn allow the helper to be reused nearly verbatim
for addr_gva2gpa().

Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20221006004512.666529-3-seanjc@google.com
This commit is contained in:
Sean Christopherson 2022-10-06 00:45:07 +00:00
parent 816c54b747
commit 751f280017
3 changed files with 3 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
tools/testing/selftests/kvm/include/x86_64/processor.h
View File

@ -827,8 +827,7 @@ static inline uint8_t wrmsr_safe(uint32_t msr, uint64_t val)
bool kvm_is_tdp_enabled(void);
uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
uint64_t vaddr);
uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr);
uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2,
uint64_t a3);

26
tools/testing/selftests/kvm/lib/x86_64/processor.c
View File

@ -241,29 +241,11 @@ void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr,
}
}
uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
uint64_t vaddr)
uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr)
{
uint16_t index[4];
uint64_t *pml4e, *pdpe, *pde;
uint64_t *pte;
struct kvm_sregs sregs;
uint64_t rsvd_mask = 0;
/* Set the high bits in the reserved mask. */
if (vm->pa_bits < 52)
rsvd_mask = GENMASK_ULL(51, vm->pa_bits);
/*
* SDM vol 3, fig 4-11 "Formats of CR3 and Paging-Structure Entries
* with 4-Level Paging and 5-Level Paging".
* If IA32_EFER.NXE = 0 and the P flag of a paging-structure entry is 1,
* the XD flag (bit 63) is reserved.
*/
vcpu_sregs_get(vcpu, &sregs);
if ((sregs.efer & EFER_NX) == 0) {
rsvd_mask |= PTE_NX_MASK;
}
TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
"unknown or unsupported guest mode, mode: 0x%x", vm->mode);
@ -286,24 +268,18 @@ uint64_t *vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
pml4e = addr_gpa2hva(vm, vm->pgd);
TEST_ASSERT(pml4e[index[3]] & PTE_PRESENT_MASK,
"Expected pml4e to be present for gva: 0x%08lx", vaddr);
TEST_ASSERT((pml4e[index[3]] & (rsvd_mask | PTE_LARGE_MASK)) == 0,
"Unexpected reserved bits set.");
pdpe = addr_gpa2hva(vm, PTE_GET_PFN(pml4e[index[3]]) * vm->page_size);
TEST_ASSERT(pdpe[index[2]] & PTE_PRESENT_MASK,
"Expected pdpe to be present for gva: 0x%08lx", vaddr);
TEST_ASSERT(!(pdpe[index[2]] & PTE_LARGE_MASK),
"Expected pdpe to map a pde not a 1-GByte page.");
TEST_ASSERT((pdpe[index[2]] & rsvd_mask) == 0,
"Unexpected reserved bits set.");
pde = addr_gpa2hva(vm, PTE_GET_PFN(pdpe[index[2]]) * vm->page_size);
TEST_ASSERT(pde[index[1]] & PTE_PRESENT_MASK,
"Expected pde to be present for gva: 0x%08lx", vaddr);
TEST_ASSERT(!(pde[index[1]] & PTE_LARGE_MASK),
"Expected pde to map a pte not a 2-MByte page.");
TEST_ASSERT((pde[index[1]] & rsvd_mask) == 0,
"Unexpected reserved bits set.");
pte = addr_gpa2hva(vm, PTE_GET_PFN(pde[index[1]]) * vm->page_size);
TEST_ASSERT(pte[index[0]] & PTE_PRESENT_MASK,

2
tools/testing/selftests/kvm/x86_64/emulator_error_test.c
View File

@ -180,7 +180,7 @@ int main(int argc, char *argv[])
hva = addr_gpa2hva(vm, MEM_REGION_GPA);
memset(hva, 0, PAGE_SIZE);
pte = vm_get_page_table_entry(vm, vcpu, MEM_REGION_GVA);
pte = vm_get_page_table_entry(vm, MEM_REGION_GVA);
*pte |= BIT_ULL(MAXPHYADDR);
vcpu_run(vcpu);