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From: Jim Mattson <jmattson@google.com>
To: kvm@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>
Subject: [PATCH 1/3] kvm: vmx: Do not disable intercepts for BNDCFGS
Date: Tue, 23 May 2017 11:52:52 -0700	[thread overview]
Message-ID: <20170523185254.98780-1-jmattson@google.com> (raw)

The MSR permission bitmaps are shared by all VMs. However, some VMs
may not be configured to support MPX, even when the host does. If the
host supports VMX and the guest does not, we should intercept accesses
to the BNDCFGS MSR, so that we can synthesize a #GP
fault. Furthermore, if the host does not support MPX and the
"ignore_msrs" kvm kernel parameter is set, then we should intercept
accesses to the BNDCFGS MSR, so that we can skip over the rdmsr/wrmsr
without raising a #GP fault.

Fixes: da8999d31818fdc8 ("KVM: x86: Intel MPX vmx and msr handle")
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/vmx.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c6f4ad44aa95..763d27ee00fb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6547,7 +6547,6 @@ static __init int hardware_setup(void)
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
 	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
-	vmx_disable_intercept_for_msr(MSR_IA32_BNDCFGS, true);
 
 	memcpy(vmx_msr_bitmap_legacy_x2apic_apicv,
 			vmx_msr_bitmap_legacy, PAGE_SIZE);
-- 
2.13.0.219.gdb65acc882-goog

             reply	other threads:[~2017-05-23 18:53 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-23 18:52 Jim Mattson [this message]
2017-05-23 18:52 ` [PATCH 2/3] kvm: vmx: Guest BNDCFGS requires guest MPX support Jim Mattson
2017-05-24 13:08   ` kbuild test robot
2017-05-24 16:22     ` [PATCH 2/3 v2] kvm: x86: " Jim Mattson
2017-05-24 17:28       ` Radim Krčmář
2017-05-24 17:40         ` Jim Mattson
2017-05-24 17:49           ` [PATCH 2/3 v3] " Jim Mattson
2017-05-24 18:22             ` Radim Krčmář
2017-05-23 18:52 ` [PATCH 3/3] kvm: vmx: Check value written to IA32_BNDCFGS Jim Mattson
2017-05-24 15:09   ` Radim Krčmář
2017-05-24 15:05 ` [PATCH 1/3] kvm: vmx: Do not disable intercepts for BNDCFGS Radim Krčmář
2017-06-07 14:31 ` Radim Krčmář

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