[PATCH v6 1/9] x86/cpu: Add new VMX feature, Tertiary VM-Execution control

Zeng Guang
2022-02-25T08:53:29Z

From: Robert Hoo <robert.hu@linux.intel.com>

A new 64-bit control field "tertiary processor-based VM-execution
controls", is defined [1]. It's controlled by bit 17 of the primary
processor-based VM-execution controls.

Different from its brother VM-execution fields, this tertiary VM-
execution controls field is 64 bit. So it occupies 2 vmx_feature_leafs,
TERTIARY_CTLS_LOW and TERTIARY_CTLS_HIGH.

Its companion VMX capability reporting MSR,MSR_IA32_VMX_PROCBASED_CTLS3
(0x492), is also semantically different from its brothers, whose 64 bits
consist of all allow-1, rather than 32-bit allow-0 and 32-bit allow-1 [1][2].
Therefore, its init_vmx_capabilities() is a little different from others.

[1] ISE 6.2 "VMCS Changes"
https://www.intel.com/content/www/us/en/develop/download/intel-architecture-instruction-set-extensions-programming-reference.html

[2] SDM Vol3. Appendix A.3

Signed-off-by: Robert Hoo <robert.hu@linux.intel.com>
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/include/asm/vmxfeatures.h | 3 ++-
arch/x86/kernel/cpu/feat_ctl.c | 9 ++++++++-
3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 3faf0f97edb1..1d180f883c32 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -938,6 +938,7 @@
#define MSR_IA32_VMX_TRUE_EXIT_CTLS 0x0000048f
#define MSR_IA32_VMX_TRUE_ENTRY_CTLS 0x00000490
#define MSR_IA32_VMX_VMFUNC 0x00000491
+#define MSR_IA32_VMX_PROCBASED_CTLS3 0x00000492

/* VMX_BASIC bits and bitmasks */
#define VMX_BASIC_VMCS_SIZE_SHIFT 32
diff --git a/arch/x86/include/asm/vmxfeatures.h b/arch/x86/include/asm/vmxfeatures.h
index d9a74681a77d..ff20776dc83b 100644
--- a/arch/x86/include/asm/vmxfeatures.h
+++ b/arch/x86/include/asm/vmxfeatures.h
@@ -5,7 +5,7 @@
/*
* Defines VMX CPU feature bits
*/
-#define NVMXINTS 3 /* N 32-bit words worth of info */
+#define NVMXINTS 5 /* N 32-bit words worth of info */

/*
* Note: If the comment begins with a quoted string, that string is used
@@ -43,6 +43,7 @@
#define VMX_FEATURE_RDTSC_EXITING ( 1*32+ 12) /* "" VM-Exit on RDTSC */
#define VMX_FEATURE_CR3_LOAD_EXITING ( 1*32+ 15) /* "" VM-Exit on writes to CR3 */
#define VMX_FEATURE_CR3_STORE_EXITING ( 1*32+ 16) /* "" VM-Exit on reads from CR3 */
+#define VMX_FEATURE_TERTIARY_CONTROLS ( 1*32+ 17) /* "" Enable Tertiary VM-Execution Controls */
#define VMX_FEATURE_CR8_LOAD_EXITING ( 1*32+ 19) /* "" VM-Exit on writes to CR8 */
#define VMX_FEATURE_CR8_STORE_EXITING ( 1*32+ 20) /* "" VM-Exit on reads from CR8 */
#define VMX_FEATURE_VIRTUAL_TPR ( 1*32+ 21) /* "vtpr" TPR virtualization, a.k.a. TPR shadow */
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index da696eb4821a..993697e71854 100644
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -15,6 +15,8 @@ enum vmx_feature_leafs {
MISC_FEATURES = 0,
PRIMARY_CTLS,
SECONDARY_CTLS,
+ TERTIARY_CTLS_LOW,
+ TERTIARY_CTLS_HIGH,
NR_VMX_FEATURE_WORDS,
};

@@ -22,7 +24,7 @@ enum vmx_feature_leafs {

static void init_vmx_capabilities(struct cpuinfo_x86 *c)
{
- u32 supported, funcs, ept, vpid, ign;
+ u32 supported, funcs, ept, vpid, ign, low, high;

BUILD_BUG_ON(NVMXINTS != NR_VMX_FEATURE_WORDS);

@@ -42,6 +44,11 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS2, &ign, &supported);
c->vmx_capability[SECONDARY_CTLS] = supported;

+ /* All 64 bits of tertiary controls MSR are allowed-1 settings. */
+ rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS3, &low, &high);
+ c->vmx_capability[TERTIARY_CTLS_LOW] = low;
+ c->vmx_capability[TERTIARY_CTLS_HIGH] = high;
+
rdmsr(MSR_IA32_VMX_PINBASED_CTLS, ign, supported);
rdmsr_safe(MSR_IA32_VMX_VMFUNC, &ign, &funcs);

--
2.27.0