Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: CS7krmnNGQSxPozfZw5e2p28Fouh+ddThmW/2Z97RCztoZE/027+AvIgf38NcR7SKfi+z2iFsD
 P+XDwbHzZlKg==
IronPort-SDR: ywuLMY040oWwJro92QHR0lHKimxFI4iRXa/MiR2z6+0/95VIvr99RI4jC812JLXrm+GLEDHTPH
 hCpADSMoVYlA==
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
Subject: [PATCH v3 10/11] KVM: VMX: Skip additional Hyper-V TLB EPTP flushes if one fails
Date:   Tue, 27 Oct 2020 14:23:45 -0700
Message-Id: <20201027212346.23409-11-sean.j.christopherson@intel.com>
In-Reply-To: <20201027212346.23409-1-sean.j.christopherson@intel.com>
References: <20201027212346.23409-1-sean.j.christopherson@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@intel.com>
---
 arch/x86/kvm/vmx/vmx.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5b7c5b2fd2c7..40a67dd45c8c 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -528,7 +528,15 @@ static int hv_remote_flush_tlb_with_range(struct kvm *kvm,
 			if (++nr_unique_valid_eptps == 1)
 				kvm_vmx->hv_tlb_eptp = tmp_eptp;
 
-			ret |= hv_remote_flush_eptp(tmp_eptp, range);
+			if (!ret)
+				ret = hv_remote_flush_eptp(tmp_eptp, range);
+
+			/*
+			 * Stop processing EPTPs if a failure occurred and
+			 * there is already a detected EPTP mismatch.
+			 */
+			if (ret && nr_unique_valid_eptps > 1)
+				break;
 		}
 
 		/*
-- 
2.28.0