[PATCH v4 01/19] x86/msr-index: Clean up bit defines for IA32_FEATURE_CONTROL MSR

Sean Christopherson
2019-11-28T01:40:24Z

As pointed out by Boris, the defines for bits in IA32_FEATURE_CONTROL
are quite a mouthful, especially the VMX bits which must differentiate
between enabling VMX inside and outside SMX (TXT) operation. Rename the
MSR and its bit defines to abbreviate FEATURE_CONTROL as FEAT_CTL to
make them a little friendlier on the eyes.

Arguably the MSR itself should keep the full IA32_FEATURE_CONTROL name
to match Intel's SDM, but a future patch will add a dedicated Kconfig,
file and functions for the MSR. Using the full name for those assets is
rather unwieldy, so bite the bullet and use IA32_FEAT_CTL so that its
nomenclature is consistent throughout the kernel.

Opportunistically fix a few other annoyances with the defines:

- Relocate the bit defines so that they immediately follow the MSR
define, e.g. aren't mistaken as belonging to MISC_FEATURE_CONTROL.
- Add whitespace around the block of feature control defines to make
it clear they're all related.
- Use BIT() instead of manually encoding the bit shift.
- Use "VMX" instead of "VMXON" to match the SDM.
- Append "_ENABLED" to the LMCE (Local Machine Check Exception) bit to
be consistent with the kernel's verbiage used for all other feature
control bits. Note, the SDM refers to the LMCE bit as LMCE_ON,
likely to differentiate it from IA32_MCG_EXT_CTL.LMCE_EN. Ignore
the (literal) one-off usage of _ON, the SDM is simply "wrong".

Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/include/asm/msr-index.h | 14 +++++-----
arch/x86/kernel/cpu/mce/intel.c | 10 +++----
arch/x86/kvm/vmx/nested.c | 4 +--
arch/x86/kvm/vmx/vmx.c | 46 ++++++++++++++++----------------
arch/x86/kvm/vmx/vmx.h | 2 +-
arch/x86/kvm/x86.c | 2 +-
6 files changed, 40 insertions(+), 38 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 084e98da04a7..ebe1685e92dd 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -558,7 +558,14 @@
#define MSR_IA32_EBL_CR_POWERON 0x0000002a
#define MSR_EBC_FREQUENCY_ID 0x0000002c
#define MSR_SMI_COUNT 0x00000034
-#define MSR_IA32_FEATURE_CONTROL 0x0000003a
+
+/* Referred to as IA32_FEATURE_CONTROL in Intel's SDM. */
+#define MSR_IA32_FEAT_CTL 0x0000003a
+#define FEAT_CTL_LOCKED BIT(0)
+#define FEAT_CTL_VMX_ENABLED_INSIDE_SMX BIT(1)
+#define FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX BIT(2)
+#define FEAT_CTL_LMCE_ENABLED BIT(20)
+
#define MSR_IA32_TSC_ADJUST 0x0000003b
#define MSR_IA32_BNDCFGS 0x00000d90

@@ -566,11 +573,6 @@

#define MSR_IA32_XSS 0x00000da0

-#define FEATURE_CONTROL_LOCKED (1<<0)
-#define FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX (1<<1)
-#define FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX (1<<2)
-#define FEATURE_CONTROL_LMCE (1<<20)
-
#define MSR_IA32_APICBASE 0x0000001b
#define MSR_IA32_APICBASE_BSP (1<<8)
#define MSR_IA32_APICBASE_ENABLE (1<<11)
diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
index e270d0770134..c238518b84a2 100644
--- a/arch/x86/kernel/cpu/mce/intel.c
+++ b/arch/x86/kernel/cpu/mce/intel.c
@@ -115,12 +115,12 @@ static bool lmce_supported(void)

/*
* BIOS should indicate support for LMCE by setting bit 20 in
- * IA32_FEATURE_CONTROL without which touching MCG_EXT_CTL will
- * generate a #GP fault.
+ * IA32_FEAT_CTL without which touching MCG_EXT_CTL will generate a #GP
+ * fault.
*/
- rdmsrl(MSR_IA32_FEATURE_CONTROL, tmp);
- if ((tmp & (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_LMCE)) ==
- (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_LMCE))
+ rdmsrl(MSR_IA32_FEAT_CTL, tmp);
+ if ((tmp & (FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED)) ==
+ (FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED))
return true;

return false;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 4aea7d304beb..6879966b7648 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4588,8 +4588,8 @@ static int handle_vmon(struct kvm_vcpu *vcpu)
gpa_t vmptr;
uint32_t revision;
struct vcpu_vmx *vmx = to_vmx(vcpu);
- const u64 VMXON_NEEDED_FEATURES = FEATURE_CONTROL_LOCKED
- | FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
+ const u64 VMXON_NEEDED_FEATURES = FEAT_CTL_LOCKED
+ | FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;

/*
* The Intel VMX Instruction Reference lists a bunch of bits that are
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 1b9ab4166397..ecf3ccf71bb2 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1839,11 +1839,11 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_MCG_EXT_CTL:
if (!msr_info->host_initiated &&
!(vmx->msr_ia32_feature_control &
- FEATURE_CONTROL_LMCE))
+ FEAT_CTL_LMCE_ENABLED))
return 1;
msr_info->data = vcpu->arch.mcg_ext_ctl;
break;
- case MSR_IA32_FEATURE_CONTROL:
+ case MSR_IA32_FEAT_CTL:
msr_info->data = vmx->msr_ia32_feature_control;
break;
case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
@@ -2074,15 +2074,15 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_MCG_EXT_CTL:
if ((!msr_info->host_initiated &&
!(to_vmx(vcpu)->msr_ia32_feature_control &
- FEATURE_CONTROL_LMCE)) ||
+ FEAT_CTL_LMCE_ENABLED)) ||
(data & ~MCG_EXT_CTL_LMCE_EN))
return 1;
vcpu->arch.mcg_ext_ctl = data;
break;
- case MSR_IA32_FEATURE_CONTROL:
+ case MSR_IA32_FEAT_CTL:
if (!vmx_feature_control_msr_valid(vcpu, data) ||
(to_vmx(vcpu)->msr_ia32_feature_control &
- FEATURE_CONTROL_LOCKED && !msr_info->host_initiated))
+ FEAT_CTL_LOCKED && !msr_info->host_initiated))
return 1;
vmx->msr_ia32_feature_control = data;
if (msr_info->host_initiated && data == 0)
@@ -2206,22 +2206,22 @@ static __init int vmx_disabled_by_bios(void)
{
u64 msr;

- rdmsrl(MSR_IA32_FEATURE_CONTROL, msr);
- if (msr & FEATURE_CONTROL_LOCKED) {
+ rdmsrl(MSR_IA32_FEAT_CTL, msr);
+ if (msr & FEAT_CTL_LOCKED) {
/* launched w/ TXT and VMX disabled */
- if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
+ if (!(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)
&& tboot_enabled())
return 1;
/* launched w/o TXT and VMX only enabled w/ TXT */
- if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
- && (msr & FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX)
+ if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX)
+ && (msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)
&& !tboot_enabled()) {
printk(KERN_WARNING "kvm: disable TXT in the BIOS or "
"activate TXT before enabling KVM\n");
return 1;
}
/* launched w/o TXT and VMX disabled */
- if (!(msr & FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX)
+ if (!(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX)
&& !tboot_enabled())
return 1;
}
@@ -2269,16 +2269,16 @@ static int hardware_enable(void)
*/
crash_enable_local_vmclear(cpu);

- rdmsrl(MSR_IA32_FEATURE_CONTROL, old);
+ rdmsrl(MSR_IA32_FEAT_CTL, old);

- test_bits = FEATURE_CONTROL_LOCKED;
- test_bits |= FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
+ test_bits = FEAT_CTL_LOCKED;
+ test_bits |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
if (tboot_enabled())
- test_bits |= FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX;
+ test_bits |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;

if ((old & test_bits) != test_bits) {
/* enable and lock */
- wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits);
+ wrmsrl(MSR_IA32_FEAT_CTL, old | test_bits);
}
kvm_cpu_vmxon(phys_addr);
if (enable_ept)
@@ -6807,7 +6807,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
vmx->nested.posted_intr_nv = -1;
vmx->nested.current_vmptr = -1ull;

- vmx->msr_ia32_feature_control_valid_bits = FEATURE_CONTROL_LOCKED;
+ vmx->msr_ia32_feature_control_valid_bits = FEAT_CTL_LOCKED;

/*
* Enforce invariant: pi_desc.nv is always either POSTED_INTR_VECTOR
@@ -7107,12 +7107,12 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)

if (nested_vmx_allowed(vcpu))
to_vmx(vcpu)->msr_ia32_feature_control_valid_bits |=
- FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX |
- FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX;
+ FEAT_CTL_VMX_ENABLED_INSIDE_SMX |
+ FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
else
to_vmx(vcpu)->msr_ia32_feature_control_valid_bits &=
- ~(FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX |
- FEATURE_CONTROL_VMXON_ENABLED_OUTSIDE_SMX);
+ ~(FEAT_CTL_VMX_ENABLED_INSIDE_SMX |
+ FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX);

if (nested_vmx_allowed(vcpu)) {
nested_vmx_cr_fixed1_bits_update(vcpu);
@@ -7531,10 +7531,10 @@ static void vmx_setup_mce(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.mcg_cap & MCG_LMCE_P)
to_vmx(vcpu)->msr_ia32_feature_control_valid_bits |=
- FEATURE_CONTROL_LMCE;
+ FEAT_CTL_LMCE_ENABLED;
else
to_vmx(vcpu)->msr_ia32_feature_control_valid_bits &=
- ~FEATURE_CONTROL_LMCE;
+ ~FEAT_CTL_LMCE_ENABLED;
}

static int vmx_smi_allowed(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 7c1b978b2df4..b2c87f6be987 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -283,7 +283,7 @@ struct vcpu_vmx {

/*
* Only bits masked by msr_ia32_feature_control_valid_bits can be set in
- * msr_ia32_feature_control. FEATURE_CONTROL_LOCKED is always included
+ * msr_ia32_feature_control. FEAT_CTL_LOCKED is always included
* in msr_ia32_feature_control_valid_bits.
*/
u64 msr_ia32_feature_control;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cf917139de6b..740d3ee42455 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1142,7 +1142,7 @@ static const u32 msrs_to_save_all[] = {
MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR,
#endif
MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
- MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
+ MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
MSR_IA32_SPEC_CTRL,
MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
--
2.24.0