From: Huaitong Han <huaitong.han@intel.com>
Date: Tue, 12 Jan 2016 08:04:20 +0000 (+0800)
Subject: kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL
X-Git-Tag: Ubuntu-snapdragon-4.4.0-1050.54~6878
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=e24ed5519f61b7a5f4d660f1e0c4cabd6cf499fc;p=mirror_ubuntu-artful-kernel.git

kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL

commit 45bdbcfdf241149642fb6c25ab0c209d59c371b7 upstream.

vmx_cpuid_tries to update SECONDARY_VM_EXEC_CONTROL in the VMCS, but
it will cause a vmwrite error on older CPUs because the code does not
check for the presence of CPU_BASED_ACTIVATE_SECONDARY_CONTROLS.

This will get rid of the following trace on e.g. Core2 6600:

vmwrite error: reg 401e value 10 (err 12)
Call Trace:
[<ffffffff8116e2b9>] dump_stack+0x40/0x57
[<ffffffffa020b88d>] vmx_cpuid_update+0x5d/0x150 [kvm_intel]
[<ffffffffa01d8fdc>] kvm_vcpu_ioctl_set_cpuid2+0x4c/0x70 [kvm]
[<ffffffffa01b8363>] kvm_arch_vcpu_ioctl+0x903/0xfa0 [kvm]

Fixes: feda805fe7c4ed9cf78158e73b1218752e3b4314
Reported-by: Zdenek Kaspar <zkaspar82@gmail.com>
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 44976a596fa6..10e7693b3540 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8932,7 +8932,8 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 			best->ebx &= ~bit(X86_FEATURE_INVPCID);
 	}
 
-	vmcs_set_secondary_exec_control(secondary_exec_ctl);
+	if (cpu_has_secondary_exec_ctrls())
+		vmcs_set_secondary_exec_control(secondary_exec_ctl);
 
 	if (static_cpu_has(X86_FEATURE_PCOMMIT) && nested) {
 		if (guest_cpuid_has_pcommit(vcpu))