From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Kai Huang <kai.huang@intel.com>
Subject: [PATCH 1/4] KVM: x86/mmu: Return -EIO if page fault returns RET_PF_INVALID
Date: Wed, 23 Sep 2020 15:04:22 -0700 [thread overview]
Message-ID: <20200923220425.18402-2-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200923220425.18402-1-sean.j.christopherson@intel.com>
Exit to userspace with an error if the MMU is buggy and returns
RET_PF_INVALID when servicing a page fault. This will allow a future
patch to invert the emulation path, i.e. emulate only on RET_PF_EMULATE
instead of emulating on anything but RET_PF_RETRY. This technically
means that KVM will exit to userspace instead of emulating on
RET_PF_INVALID, but practically speaking it's a nop as the MMU never
returns RET_PF_INVALID.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 76c5826e29a2..4a2a8f67a8f7 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5450,7 +5450,8 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
if (r == RET_PF_INVALID) {
r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa,
lower_32_bits(error_code), false);
- WARN_ON(r == RET_PF_INVALID);
+ if (WARN_ON_ONCE(r == RET_PF_INVALID))
+ return -EIO;
}
if (r == RET_PF_RETRY)
--
2.28.0
next prev parent reply other threads:[~2020-09-23 22:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 22:04 [PATCH 0/4] KVM: x86/mmu: Page fault handling cleanups Sean Christopherson
2020-09-23 22:04 ` Sean Christopherson [this message]
2020-09-23 22:04 ` [PATCH 2/4] KVM: x86/mmu: Invert RET_PF_* check when falling through to emulation Sean Christopherson
2020-09-23 22:04 ` [PATCH 4/4] KVM: x86/mmu: Bail early from final #PF handling on spurious faults Sean Christopherson
2020-09-25 20:38 ` [PATCH 0/4] KVM: x86/mmu: Page fault handling cleanups Paolo Bonzini
2020-09-25 20:40 ` Sean Christopherson
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