linux-kernel - [PATCH] kvm: vmx: Fix entry nubmer check for add_atomic_switch

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Message-Id: <20190214040858.15975-1-xiaoyao.li@linux.intel.com>
Date:   Thu, 14 Feb 2019 12:08:58 +0800
From:   Xiaoyao Li <xiaoyao.li@...ux.intel.com>
To:     x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Xiaoyao Li <xiaoyao.li@...ux.intel.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH] kvm: vmx: Fix entry nubmer check for add_atomic_switch_msr()

Commit ca83b4a7f2d068da79a0 ("x86/KVM/VMX: Add find_msr() helper function")
introduces the helper function find_msr(), which returns -ENOENT when
not find the msr in vmx->msr_autoload.guest/host. Correct checking contion
of no more available entry in vmx->msr_autoload.

Fixes: ca83b4a7f2d0 ("x86/KVM/VMX: Add find_msr() helper function")
Signed-off-by: Xiaoyao Li <xiaoyao.li@...ux.intel.com>
---
 arch/x86/kvm/vmx/vmx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 95d618045001..1aaef2d536bd 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -863,7 +863,8 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr,
 	if (!entry_only)
 		j = find_msr(&m->host, msr);
 
-	if (i == NR_AUTOLOAD_MSRS || j == NR_AUTOLOAD_MSRS) {
+	if ((i < 0 && m->guest.nr == NR_AUTOLOAD_MSRS) ||
+		(j < 0 &&  m->host.nr == NR_AUTOLOAD_MSRS)) {
 		printk_once(KERN_WARNING "Not enough msr switch entries. "
 				"Can't add msr %x\n", msr);
 		return;
-- 
2.19.1