[PATCH 10/28] KVM: x86/mmu: pass PFERR_GUEST_PAGE/FINAL_MASK to kvm_translate_gpa

Paolo Bonzini
2026-04-30T15:08:06Z

The XS/XU bit for EPT are only applied to final accesses, and use the
U bit from the page walk itself. While strictly speaking not necessary
(any value of PFERR_USER_MASK would be the same for page table accesses,
because they're reads and writes only), it is clearer and less hackish
to only apply MBEC to PFERR_GUEST_FINAL_MASK. Allow kvm-intel.ko to
distinguish the two cases.

Tested-by: David Riley <d.riley@proxmox.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/hyperv.c | 3 ++-
arch/x86/kvm/mmu/mmu.c | 3 ++-
arch/x86/kvm/mmu/paging_tmpl.h | 7 +++++--
arch/x86/kvm/x86.c | 3 ++-
4 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 9b140bbdc1d8..cf9dd565b894 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2041,7 +2041,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
* read with kvm_read_guest().
*/
if (!hc->fast && is_guest_mode(vcpu)) {
- hc->ingpa = translate_nested_gpa(vcpu, hc->ingpa, 0, NULL);
+ hc->ingpa = translate_nested_gpa(vcpu, hc->ingpa,
+ PFERR_GUEST_FINAL_MASK, NULL);
if (unlikely(hc->ingpa == INVALID_GPA))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index fc1b17e22ea2..0fc362508a19 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4348,7 +4348,8 @@ static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
{
if (exception)
exception->error_code = 0;
- return kvm_translate_gpa(vcpu, mmu, vaddr, access, exception);
+ return kvm_translate_gpa(vcpu, mmu, vaddr, access | PFERR_GUEST_FINAL_MASK,
+ exception);
}

static bool mmio_info_in_cache(struct kvm_vcpu *vcpu, u64 addr, bool direct)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index fb1b5d8b23e5..567f8b77ffe0 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -376,7 +376,8 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
walker->pte_gpa[walker->level - 1] = pte_gpa;

real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(table_gfn),
- nested_access, &walker->fault);
+ nested_access | PFERR_GUEST_PAGE_MASK,
+ &walker->fault);

/*
* FIXME: This can happen if emulation (for of an INS/OUTS
@@ -444,7 +445,9 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
gfn += pse36_gfn_delta(pte);
#endif

- real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(gfn), access, &walker->fault);
+ real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(gfn),
+ access | PFERR_GUEST_FINAL_MASK,
+ &walker->fault);
if (real_gpa == INVALID_GPA)
return 0;

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0a1b63c63d1a..ef1e3ae13887 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1072,7 +1072,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
* to an L1 GPA.
*/
real_gpa = kvm_translate_gpa(vcpu, mmu, gfn_to_gpa(pdpt_gfn),
- PFERR_USER_MASK | PFERR_WRITE_MASK, NULL);
+ PFERR_USER_MASK | PFERR_WRITE_MASK |
+ PFERR_GUEST_PAGE_MASK, NULL);
if (real_gpa == INVALID_GPA)
return 0;

--
2.52.0