Now that it should be impossible to convert a valid SPTE to an MMIO SPTE,
handle MMIO SPTEs early in mmu_set_spte() without going through
set_spte() and all the logic for removing an existing, valid SPTE.
The other caller of set_spte(), FNAME(sync_page)(), explicitly handles
MMIO SPTEs prior to calling set_spte().
This simplifies mmu_set_spte() and set_spte(), and also "fixes" an oddity
where MMIO SPTEs are traced by both trace_kvm_mmu_set_spte() and
trace_mark_mmio_spte().
Note, mmu_spte_set() will WARN if this new approach causes KVM to create
an MMIO SPTE overtop a valid SPTE.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/mmu/mmu.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 37c68abc54b8..4a24beefff94 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -236,17 +236,6 @@ static unsigned get_mmio_spte_access(u64 spte)
return spte & shadow_mmio_access_mask;
}
-static bool set_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
- kvm_pfn_t pfn, unsigned int access)
-{
- if (unlikely(is_noslot_pfn(pfn))) {
- mark_mmio_spte(vcpu, sptep, gfn, access);
- return true;
- }
-
- return false;
-}
-
static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)
{
u64 kvm_gen, spte_gen, gen;
@@ -2561,9 +2550,6 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
struct kvm_mmu_page *sp;
int ret;
- if (set_mmio_spte(vcpu, sptep, gfn, pfn, pte_access))
- return 0;
-
sp = sptep_to_sp(sptep);
ret = make_spte(vcpu, pte_access, level, gfn, pfn, *sptep, speculative,
@@ -2593,6 +2579,11 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
*sptep, write_fault, gfn);
+ if (unlikely(is_noslot_pfn(pfn))) {
+ mark_mmio_spte(vcpu, sptep, gfn, pte_access);
+ return RET_PF_EMULATE;
+ }
+
if (is_shadow_present_pte(*sptep)) {
/*
* If we overwrite a PTE page pointer with a 2MB PMD, unlink
@@ -2626,9 +2617,6 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn,
KVM_PAGES_PER_HPAGE(level));
- if (unlikely(is_mmio_spte(*sptep)))
- ret = RET_PF_EMULATE;
-
/*
* The fault is fully spurious if and only if the new SPTE and old SPTE
* are identical, and emulation is not required.
--
2.30.1.766.gb4fecdf3b7-goog
