[PATCH 03/15] x86/feat_ctl: Add new VMX feature, Tertiary VM-Execution control and LOADIWKEY Exiting

From: Robert Hoo
Date: Tue Jun 01 2021 - 04:48:24 EST


There is a new VMX capability MSR IA32_VMX_PROCBASED_CTLS3.

All 64 bits of this MSR define capability bits for the new tertiary VM-Exec
control so two new 32-bit vmx_feature leaves are needed to record all the
capabilities.

The 2 new VMX features:
Tertiary VM-Execution control is enumerated by bit 17 of existing Primary
VM-Execution control.
LOADIWKEY Exiting is enumerated by bit 0 of this new tertiary VM-Exec
control, which designates if guest running 'loadiwkey' instruction will
cause VM-Exit.

Signed-off-by: Robert Hoo <robert.hu@xxxxxxxxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/include/asm/vmxfeatures.h | 6 +++++-
arch/x86/kernel/cpu/feat_ctl.c | 9 +++++++++
3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index f8e7878..dd103c2 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -915,6 +915,7 @@
#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 d9a7468..c0b2f63 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_TER_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 */
@@ -85,4 +86,7 @@
#define VMX_FEATURE_ENCLV_EXITING ( 2*32+ 28) /* "" VM-Exit on ENCLV (leaf dependent) */
#define VMX_FEATURE_BUS_LOCK_DETECTION ( 2*32+ 30) /* "" VM-Exit when bus lock caused */

+/* Tertiary Processor-Based VM-Execution Controls, word 3 */
+#define VMX_FEATURE_LOADIWKEY_EXITING (3*32 + 0) /* "" VM-Exit on LOADIWKey */
+
#endif /* _ASM_X86_VMXFEATURES_H */
diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index da696eb..2e0272d 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,
};

@@ -42,6 +44,13 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS2, &ign, &supported);
c->vmx_capability[SECONDARY_CTLS] = supported;

+ /*
+ * For tertiary execution controls MSR, it's actually a 64bit allowed-1.
+ */
+ rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS3, &ign, &supported);
+ c->vmx_capability[TERTIARY_CTLS_LOW] = ign;
+ c->vmx_capability[TERTIARY_CTLS_HIGH] = supported;
+
rdmsr(MSR_IA32_VMX_PINBASED_CTLS, ign, supported);
rdmsr_safe(MSR_IA32_VMX_VMFUNC, &ign, &funcs);

--
1.8.3.1