From 7bd7ded642978feeec8f2b9a2b05d8e1daeff758 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <sean.j.christopherson@intel.com> Date: Tue, 23 Jun 2020 12:35:42 -0700 Subject: [PATCH] KVM: x86/mmu: Exit to userspace on make_mmu_pages_available() error Propagate any error returned by make_mmu_pages_available() out to userspace instead of resuming the guest if the error occurs while handling a page fault. Now that zapping the oldest MMU pages skips active roots, i.e. fails if and only if there are no zappable pages, there is no chance for a false positive, i.e. no chance of returning a spurious error to userspace. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Message-Id: <20200623193542.7554-5-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/mmu/mmu.c | 3 ++- arch/x86/kvm/mmu/paging_tmpl.h | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 8083ec32a0dd5..53d6bd07f9e98 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4148,7 +4148,8 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, spin_lock(&vcpu->kvm->mmu_lock); if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) goto out_unlock; - if (make_mmu_pages_available(vcpu) < 0) + r = make_mmu_pages_available(vcpu); + if (r) goto out_unlock; r = __direct_map(vcpu, gpa, write, map_writable, max_level, pfn, prefault, is_tdp && lpage_disallowed); diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 7e370d8bd5765..4ec044af36e8e 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -866,7 +866,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code, goto out_unlock; kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT); - if (make_mmu_pages_available(vcpu) < 0) + r = make_mmu_pages_available(vcpu); + if (r) goto out_unlock; r = FNAME(fetch)(vcpu, addr, &walker, write_fault, max_level, pfn, map_writable, prefault, lpage_disallowed); -- 2.30.2