Commit f3747a5a authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini

KVM: x86/mmu: Topup memory caches after walking GVA->GPA

Topup memory caches after walking the GVA->GPA translation during a
shadow page fault, there is no need to ensure the caches are full when
walking the GVA.  As of commit f5a1e9f8 ("KVM: MMU: remove call
to kvm_mmu_pte_write from walk_addr"), the FNAME(walk_addr) flow no
longer add rmaps via kvm_mmu_pte_write().

This avoids allocating memory in the case that the GVA is unmapped in
the guest, and also provides a paper trail of why/when the memory caches
need to be filled.
Reviewed-by: default avatarBen Gardon <bgardon@google.com>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200703023545.8771-8-sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 83291445
...@@ -789,10 +789,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code, ...@@ -789,10 +789,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code); pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
/* /*
* If PFEC.RSVD is set, this is a shadow page fault. * If PFEC.RSVD is set, this is a shadow page fault.
* The bit needs to be cleared before walking guest page tables. * The bit needs to be cleared before walking guest page tables.
...@@ -820,6 +816,10 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code, ...@@ -820,6 +816,10 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
return RET_PF_EMULATE; return RET_PF_EMULATE;
} }
r = mmu_topup_memory_caches(vcpu);
if (r)
return r;
vcpu->arch.write_fault_to_shadow_pgtable = false; vcpu->arch.write_fault_to_shadow_pgtable = false;
is_self_change_mapping = FNAME(is_self_change_mapping)(vcpu, is_self_change_mapping = FNAME(is_self_change_mapping)(vcpu,
......
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