[PATCH v2 09/10] KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails

From: Sean Christopherson
Date: Tue Oct 20 2020 - 17:56:30 EST


Skip additional EPTP flushes if one fails when processing EPTPs for
Hyper-V's paravirt TLB flushing. If _any_ flush fails, KVM falls back
to a full global flush, i.e. additional flushes are unnecessary (and
will likely fail anyways).

Continue processing the loop unless a mismatch was already detected,
e.g. to handle the case where the first flush fails and there is a
yet-to-be-detected mismatch.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a45a90d44d24..e0fea09a6e42 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -517,7 +517,11 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
else
mismatch = true;

- ret |= hv_remote_flush_eptp(tmp_eptp, range);
+ if (!ret)
+ ret = hv_remote_flush_eptp(tmp_eptp, range);
+
+ if (ret && mismatch)
+ break;
}
if (mismatch)
kvm_vmx->hv_tlb_eptp = INVALID_PAGE;
--
2.28.0