KVM: x86/mmu: Exit to userspace on make_mmu_pages_available() error (7bd7ded6) · Commits · 戴 / test

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

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

arch/x86/kvm/mmu/paging_tmpl.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

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