x86/cpu: Detect VMX features on Intel, Centaur and Zhaoxin CPUs

Add an entry in struct cpuinfo_x86 to track VMX capabilities and fill
the capabilities during IA32_FEAT_CTL MSR initialization.

Make the VMX capabilities dependent on IA32_FEAT_CTL and
X86_FEATURE_NAMES so as to avoid unnecessary overhead on CPUs that can't
possibly support VMX, or when /proc/cpuinfo is not available.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20191221044513.21680-11-sean.j.christopherson@intel.com

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 526425fcaedc9b415f95a37cc28d43ba82c76a04..bc3a497c029c69d9d9e24215886fb2b97b8fc380 100644 (file)
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -391,6 +391,10 @@ config IA32_FEAT_CTL
        def_bool y
        depends on CPU_SUP_INTEL || CPU_SUP_CENTAUR || CPU_SUP_ZHAOXIN
 
+config X86_VMX_FEATURE_NAMES
+       def_bool y
+       depends on IA32_FEAT_CTL && X86_FEATURE_NAMES
+
 menuconfig PROCESSOR_SELECT
        bool "Supported processor vendors" if EXPERT
        ---help---

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b49b88bae92f3cc29721742afbb8bb5544e454b1..6fb4870ed759aadf3b014485df2f8afdf9b22ab5 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -85,6 +85,9 @@ struct cpuinfo_x86 {
 #ifdef CONFIG_X86_64
        /* Number of 4K pages in DTLB/ITLB combined(in pages): */
        int                     x86_tlbsize;
+#endif
+#ifdef CONFIG_X86_VMX_FEATURE_NAMES
+       __u32                   vmx_capability[NVMXINTS];
 #endif
        __u8                    x86_virt_bits;
        __u8                    x86_phys_bits;

diff --git a/arch/x86/include/asm/vmxfeatures.h b/arch/x86/include/asm/vmxfeatures.h
index 4c743ba40ff1c1af71b60b793e3616a36363c063..0d04d8bf15a59133b3ed46e47d2c8aca7dae8410 100644 (file)
--- a/arch/x86/include/asm/vmxfeatures.h
+++ b/arch/x86/include/asm/vmxfeatures.h
@@ -2,6 +2,11 @@
 #ifndef _ASM_X86_VMXFEATURES_H
 #define _ASM_X86_VMXFEATURES_H
 
+/*
+ * Defines VMX CPU feature bits
+ */
+#define NVMXINTS                       3 /* N 32-bit words worth of info */
+
 /*
  * Note: If the comment begins with a quoted string, that string is used
  * in /proc/cpuinfo instead of the macro name.  If the string is "",

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 2e4d90294fe67cded7b5baa2b465c4f8008b6880..a5c526e004ae94b4c9cbf5d07c9ab138364402ee 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1449,6 +1449,9 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 #endif
        c->x86_cache_alignment = c->x86_clflush_size;
        memset(&c->x86_capability, 0, sizeof(c->x86_capability));
+#ifdef CONFIG_X86_VMX_FEATURE_NAMES
+       memset(&c->vmx_capability, 0, sizeof(c->vmx_capability));
+#endif
 
        generic_identify(c);
 

diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
index a46c9e46f93785396551866c3ffb569ff571df1d..cbd8bfe9b87b2b353aca1d969afe8448ce78a223 100644 (file)
--- a/arch/x86/kernel/cpu/feat_ctl.c
+++ b/arch/x86/kernel/cpu/feat_ctl.c
@@ -4,10 +4,80 @@
 #include <asm/cpufeature.h>
 #include <asm/msr-index.h>
 #include <asm/processor.h>
+#include <asm/vmx.h>
 
 #undef pr_fmt
 #define pr_fmt(fmt)    "x86/cpu: " fmt
 
+#ifdef CONFIG_X86_VMX_FEATURE_NAMES
+enum vmx_feature_leafs {
+       MISC_FEATURES = 0,
+       PRIMARY_CTLS,
+       SECONDARY_CTLS,
+       NR_VMX_FEATURE_WORDS,
+};
+
+#define VMX_F(x) BIT(VMX_FEATURE_##x & 0x1f)
+
+static void init_vmx_capabilities(struct cpuinfo_x86 *c)
+{
+       u32 supported, funcs, ept, vpid, ign;
+
+       BUILD_BUG_ON(NVMXINTS != NR_VMX_FEATURE_WORDS);
+
+       /*
+        * The high bits contain the allowed-1 settings, i.e. features that can
+        * be turned on.  The low bits contain the allowed-0 settings, i.e.
+        * features that can be turned off.  Ignore the allowed-0 settings,
+        * if a feature can be turned on then it's supported.
+        *
+        * Use raw rdmsr() for primary processor controls and pin controls MSRs
+        * as they exist on any CPU that supports VMX, i.e. we want the WARN if
+        * the RDMSR faults.
+        */
+       rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, ign, supported);
+       c->vmx_capability[PRIMARY_CTLS] = supported;
+
+       rdmsr_safe(MSR_IA32_VMX_PROCBASED_CTLS2, &ign, &supported);
+       c->vmx_capability[SECONDARY_CTLS] = supported;
+
+       rdmsr(MSR_IA32_VMX_PINBASED_CTLS, ign, supported);
+       rdmsr_safe(MSR_IA32_VMX_VMFUNC, &ign, &funcs);
+
+       /*
+        * Except for EPT+VPID, which enumerates support for both in a single
+        * MSR, low for EPT, high for VPID.
+        */
+       rdmsr_safe(MSR_IA32_VMX_EPT_VPID_CAP, &ept, &vpid);
+
+       /* Pin, EPT, VPID and VM-Func are merged into a single word. */
+       WARN_ON_ONCE(supported >> 16);
+       WARN_ON_ONCE(funcs >> 4);
+       c->vmx_capability[MISC_FEATURES] = (supported & 0xffff) |
+                                          ((vpid & 0x1) << 16) |
+                                          ((funcs & 0xf) << 28);
+
+       /* EPT bits are full on scattered and must be manually handled. */
+       if (ept & VMX_EPT_EXECUTE_ONLY_BIT)
+               c->vmx_capability[MISC_FEATURES] |= VMX_F(EPT_EXECUTE_ONLY);
+       if (ept & VMX_EPT_AD_BIT)
+               c->vmx_capability[MISC_FEATURES] |= VMX_F(EPT_AD);
+       if (ept & VMX_EPT_1GB_PAGE_BIT)
+               c->vmx_capability[MISC_FEATURES] |= VMX_F(EPT_1GB);
+
+       /* Synthetic APIC features that are aggregates of multiple features. */
+       if ((c->vmx_capability[PRIMARY_CTLS] & VMX_F(VIRTUAL_TPR)) &&
+           (c->vmx_capability[SECONDARY_CTLS] & VMX_F(VIRT_APIC_ACCESSES)))
+               c->vmx_capability[MISC_FEATURES] |= VMX_F(FLEXPRIORITY);
+
+       if ((c->vmx_capability[PRIMARY_CTLS] & VMX_F(VIRTUAL_TPR)) &&
+           (c->vmx_capability[SECONDARY_CTLS] & VMX_F(APIC_REGISTER_VIRT)) &&
+           (c->vmx_capability[SECONDARY_CTLS] & VMX_F(VIRT_INTR_DELIVERY)) &&
+           (c->vmx_capability[MISC_FEATURES] & VMX_F(POSTED_INTR)))
+               c->vmx_capability[MISC_FEATURES] |= VMX_F(APICV);
+}
+#endif /* CONFIG_X86_VMX_FEATURE_NAMES */
+
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
 {
        bool tboot = tboot_enabled();
@@ -50,5 +120,9 @@ update_caps:
                pr_err_once("VMX (%s TXT) disabled by BIOS\n",
                            tboot ? "inside" : "outside");
                clear_cpu_cap(c, X86_FEATURE_VMX);
+       } else {
+#ifdef CONFIG_X86_VMX_FEATURE_NAMES
+               init_vmx_capabilities(c);
+#endif
        }
 }