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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] VMX: correct feature checks for MPX and XSAVES
commit 68eb1a4d92be58e26bd11d02b8e0317bd56294ac
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Sep 7 12:34:43 2016 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Sep 7 12:34:43 2016 +0200
VMX: correct feature checks for MPX and XSAVES
Their VMCS fields aren't tied to the respective base CPU feature flags
but instead to VMX specific ones.
Note that while the VMCS GUEST_BNDCFGS field exists if either of the
two respective features is available, MPX continues to get exposed to
guests only with both features present.
Also add the so far missing handling of
- GUEST_BNDCFGS in construct_vmcs()
- MSR_IA32_BNDCFGS in vmx_msr_{read,write}_intercept()
and mirror the extra correctness checks during MSR write to
vmx_load_msr().
Reported-by: "Rockosov, Dmitry" <dmitry.rockosov@xxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Tested-by: "Rockosov, Dmitry" <dmitry.rockosov@xxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/cpuid.c | 3 +--
xen/arch/x86/hvm/vmx/vmcs.c | 2 ++
xen/arch/x86/hvm/vmx/vmx.c | 25 ++++++++++++++++++++-----
xen/include/asm-x86/hvm/vmx/vmcs.h | 3 +++
xen/include/asm-x86/msr-index.h | 5 ++++-
5 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c
index 38e34bd..63b2db9 100644
--- a/xen/arch/x86/cpuid.c
+++ b/xen/arch/x86/cpuid.c
@@ -168,8 +168,7 @@ static void __init calculate_hvm_featureset(void)
*/
if ( cpu_has_vmx )
{
- if ( !(vmx_vmexit_control & VM_EXIT_CLEAR_BNDCFGS) ||
- !(vmx_vmentry_control & VM_ENTRY_LOAD_BNDCFGS) )
+ if ( !cpu_has_vmx_mpx )
__clear_bit(X86_FEATURE_MPX, hvm_featureset);
if ( !cpu_has_vmx_xsaves )
diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 1bd875a..0995496 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1261,6 +1261,8 @@ static int construct_vmcs(struct vcpu *v)
__vmwrite(HOST_PAT, host_pat);
__vmwrite(GUEST_PAT, guest_pat);
}
+ if ( cpu_has_vmx_mpx )
+ __vmwrite(GUEST_BNDCFGS, 0);
if ( cpu_has_vmx_xsaves )
__vmwrite(XSS_EXIT_BITMAP, 0);
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index bb7a329..306f482 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -788,14 +788,15 @@ static int vmx_load_vmcs_ctxt(struct vcpu *v, struct
hvm_hw_cpu *ctxt)
static unsigned int __init vmx_init_msr(void)
{
- return !!cpu_has_mpx + !!cpu_has_xsaves;
+ return (cpu_has_mpx && cpu_has_vmx_mpx) +
+ (cpu_has_xsaves && cpu_has_vmx_xsaves);
}
static void vmx_save_msr(struct vcpu *v, struct hvm_msr *ctxt)
{
vmx_vmcs_enter(v);
- if ( cpu_has_mpx )
+ if ( cpu_has_mpx && cpu_has_vmx_mpx )
{
__vmread(GUEST_BNDCFGS, &ctxt->msr[ctxt->count].val);
if ( ctxt->msr[ctxt->count].val )
@@ -804,7 +805,7 @@ static void vmx_save_msr(struct vcpu *v, struct hvm_msr
*ctxt)
vmx_vmcs_exit(v);
- if ( cpu_has_xsaves )
+ if ( cpu_has_xsaves && cpu_has_vmx_xsaves )
{
ctxt->msr[ctxt->count].val = v->arch.hvm_vcpu.msr_xss;
if ( ctxt->msr[ctxt->count].val )
@@ -824,13 +825,15 @@ static int vmx_load_msr(struct vcpu *v, struct hvm_msr
*ctxt)
switch ( ctxt->msr[i].index )
{
case MSR_IA32_BNDCFGS:
- if ( cpu_has_mpx )
+ if ( cpu_has_mpx && cpu_has_vmx_mpx &&
+ is_canonical_address(ctxt->msr[i].val) &&
+ !(ctxt->msr[i].val & IA32_BNDCFGS_RESERVED) )
__vmwrite(GUEST_BNDCFGS, ctxt->msr[i].val);
else if ( ctxt->msr[i].val )
err = -ENXIO;
break;
case MSR_IA32_XSS:
- if ( cpu_has_xsaves )
+ if ( cpu_has_xsaves && cpu_has_vmx_xsaves )
v->arch.hvm_vcpu.msr_xss = ctxt->msr[i].val;
else
err = -ENXIO;
@@ -2647,6 +2650,11 @@ static int vmx_msr_read_intercept(unsigned int msr,
uint64_t *msr_content)
case MSR_IA32_DEBUGCTLMSR:
__vmread(GUEST_IA32_DEBUGCTL, msr_content);
break;
+ case MSR_IA32_BNDCFGS:
+ if ( !cpu_has_mpx || !cpu_has_vmx_mpx )
+ goto gp_fault;
+ __vmread(GUEST_BNDCFGS, msr_content);
+ break;
case MSR_IA32_FEATURE_CONTROL:
case MSR_IA32_VMX_BASIC...MSR_IA32_VMX_VMFUNC:
if ( !nvmx_msr_read_intercept(msr, msr_content) )
@@ -2873,6 +2881,13 @@ static int vmx_msr_write_intercept(unsigned int msr,
uint64_t msr_content)
break;
}
+ case MSR_IA32_BNDCFGS:
+ if ( !cpu_has_mpx || !cpu_has_vmx_mpx ||
+ !is_canonical_address(msr_content) ||
+ (msr_content & IA32_BNDCFGS_RESERVED) )
+ goto gp_fault;
+ __vmwrite(GUEST_BNDCFGS, msr_content);
+ break;
case MSR_IA32_FEATURE_CONTROL:
case MSR_IA32_VMX_BASIC...MSR_IA32_VMX_TRUE_ENTRY_CTLS:
if ( !nvmx_msr_write_intercept(msr, msr_content) )
diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h
b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 1e33d9c..997f4f5 100644
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -375,6 +375,9 @@ extern u64 vmx_ept_vpid_cap;
(vmx_secondary_exec_control & SECONDARY_EXEC_ENABLE_VIRT_EXCEPTIONS)
#define cpu_has_vmx_pml \
(vmx_secondary_exec_control & SECONDARY_EXEC_ENABLE_PML)
+#define cpu_has_vmx_mpx \
+ ((vmx_vmexit_control & VM_EXIT_CLEAR_BNDCFGS) && \
+ (vmx_vmentry_control & VM_ENTRY_LOAD_BNDCFGS))
#define cpu_has_vmx_xsaves \
(vmx_secondary_exec_control & SECONDARY_EXEC_XSAVES)
#define cpu_has_vmx_tsc_scaling \
diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index 1095c81..deb82a7 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -56,7 +56,10 @@
#define MSR_IA32_DS_AREA 0x00000600
#define MSR_IA32_PERF_CAPABILITIES 0x00000345
-#define MSR_IA32_BNDCFGS 0x00000D90
+#define MSR_IA32_BNDCFGS 0x00000d90
+#define IA32_BNDCFGS_ENABLE 0x00000001
+#define IA32_BNDCFGS_PRESERVE 0x00000002
+#define IA32_BNDCFGS_RESERVED 0x00000ffc
#define MSR_IA32_XSS 0x00000da0
--
generated by git-patchbot for /home/xen/git/xen.git#master
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