lkml.org 
[lkml]   [2020]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/cpu] KVM: VMX: Use VMX feature flag to query BIOS enabling
The following commit has been merged into the x86/cpu branch of tip:

Commit-ID: a4d0b2fdbcf75ef6654713c83c316ea3a661ddc3
Gitweb: https://git.kernel.org/tip/a4d0b2fdbcf75ef6654713c83c316ea3a661ddc3
Author: Sean Christopherson <sean.j.christopherson@intel.com>
AuthorDate: Fri, 20 Dec 2019 20:45:09 -08:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Mon, 13 Jan 2020 19:19:32 +01:00

KVM: VMX: Use VMX feature flag to query BIOS enabling

Replace KVM's manual checks on IA32_FEAT_CTL with a query on the boot
CPU's MSR_IA32_FEAT_CTL and VMX feature flags. The MSR_IA32_FEAT_CTL
indicates that IA32_FEAT_CTL has been configured and that dependent
features are accurately reflected in cpufeatures, e.g. the VMX flag is
now cleared during boot if VMX isn't fully enabled via IA32_FEAT_CTL,
including the case where the MSR isn't supported.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-16-sean.j.christopherson@intel.com
---
arch/x86/kvm/vmx/vmx.c | 27 ++-------------------------
1 file changed, 2 insertions(+), 25 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a026334..06e0e52 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2204,31 +2204,8 @@ static __init int cpu_has_kvm_support(void)

static __init int vmx_disabled_by_bios(void)
{
- u64 msr;
-
- rdmsrl(MSR_IA32_FEAT_CTL, msr);
-
- if (unlikely(!(msr & FEAT_CTL_LOCKED)))
- return 1;
-
- /* launched w/ TXT and VMX disabled */
- if (!(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) &&
- tboot_enabled())
- return 1;
- /* launched w/o TXT and VMX only enabled w/ TXT */
- if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) &&
- (msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX) &&
- !tboot_enabled()) {
- pr_warn("kvm: disable TXT in the BIOS or "
- "activate TXT before enabling KVM\n");
- return 1;
- }
- /* launched w/o TXT and VMX disabled */
- if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX) &&
- !tboot_enabled())
- return 1;
-
- return 0;
+ return !boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
+ !boot_cpu_has(X86_FEATURE_VMX);
}

static void kvm_cpu_vmxon(u64 addr)
\
 
 \ /
  Last update: 2020-01-14 11:19    [W:0.144 / U:6.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site