213 lines
6.4 KiB
C
213 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/tboot.h>
|
|
|
|
#include <asm/cpu.h>
|
|
#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,
|
|
TERTIARY_CTLS_LOW,
|
|
TERTIARY_CTLS_HIGH,
|
|
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, low, high;
|
|
|
|
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;
|
|
|
|
/* 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);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/* Set the synthetic cpufeatures to preserve /proc/cpuinfo's ABI. */
|
|
if (c->vmx_capability[PRIMARY_CTLS] & VMX_F(VIRTUAL_TPR))
|
|
set_cpu_cap(c, X86_FEATURE_TPR_SHADOW);
|
|
if (c->vmx_capability[MISC_FEATURES] & VMX_F(FLEXPRIORITY))
|
|
set_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
|
|
if (c->vmx_capability[MISC_FEATURES] & VMX_F(VIRTUAL_NMIS))
|
|
set_cpu_cap(c, X86_FEATURE_VNMI);
|
|
if (c->vmx_capability[SECONDARY_CTLS] & VMX_F(EPT))
|
|
set_cpu_cap(c, X86_FEATURE_EPT);
|
|
if (c->vmx_capability[MISC_FEATURES] & VMX_F(EPT_AD))
|
|
set_cpu_cap(c, X86_FEATURE_EPT_AD);
|
|
if (c->vmx_capability[MISC_FEATURES] & VMX_F(VPID))
|
|
set_cpu_cap(c, X86_FEATURE_VPID);
|
|
}
|
|
#endif /* CONFIG_X86_VMX_FEATURE_NAMES */
|
|
|
|
static int __init nosgx(char *str)
|
|
{
|
|
setup_clear_cpu_cap(X86_FEATURE_SGX);
|
|
|
|
return 0;
|
|
}
|
|
|
|
early_param("nosgx", nosgx);
|
|
|
|
void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
|
|
{
|
|
bool enable_sgx_kvm = false, enable_sgx_driver = false;
|
|
bool tboot = tboot_enabled();
|
|
bool enable_vmx;
|
|
u64 msr;
|
|
|
|
if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
|
|
clear_cpu_cap(c, X86_FEATURE_VMX);
|
|
clear_cpu_cap(c, X86_FEATURE_SGX);
|
|
return;
|
|
}
|
|
|
|
enable_vmx = cpu_has(c, X86_FEATURE_VMX) &&
|
|
IS_ENABLED(CONFIG_KVM_INTEL);
|
|
|
|
if (cpu_has(c, X86_FEATURE_SGX) && IS_ENABLED(CONFIG_X86_SGX)) {
|
|
/*
|
|
* Separate out SGX driver enabling from KVM. This allows KVM
|
|
* guests to use SGX even if the kernel SGX driver refuses to
|
|
* use it. This happens if flexible Launch Control is not
|
|
* available.
|
|
*/
|
|
enable_sgx_driver = cpu_has(c, X86_FEATURE_SGX_LC);
|
|
enable_sgx_kvm = enable_vmx && IS_ENABLED(CONFIG_X86_SGX_KVM);
|
|
}
|
|
|
|
if (msr & FEAT_CTL_LOCKED)
|
|
goto update_caps;
|
|
|
|
/*
|
|
* Ignore whatever value BIOS left in the MSR to avoid enabling random
|
|
* features or faulting on the WRMSR.
|
|
*/
|
|
msr = FEAT_CTL_LOCKED;
|
|
|
|
/*
|
|
* Enable VMX if and only if the kernel may do VMXON at some point,
|
|
* i.e. KVM is enabled, to avoid unnecessarily adding an attack vector
|
|
* for the kernel, e.g. using VMX to hide malicious code.
|
|
*/
|
|
if (enable_vmx) {
|
|
msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
|
|
|
|
if (tboot)
|
|
msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
|
|
}
|
|
|
|
if (enable_sgx_kvm || enable_sgx_driver) {
|
|
msr |= FEAT_CTL_SGX_ENABLED;
|
|
if (enable_sgx_driver)
|
|
msr |= FEAT_CTL_SGX_LC_ENABLED;
|
|
}
|
|
|
|
wrmsrl(MSR_IA32_FEAT_CTL, msr);
|
|
|
|
update_caps:
|
|
set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL);
|
|
|
|
if (!cpu_has(c, X86_FEATURE_VMX))
|
|
goto update_sgx;
|
|
|
|
if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
|
|
(!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
|
|
if (IS_ENABLED(CONFIG_KVM_INTEL))
|
|
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
|
|
}
|
|
|
|
update_sgx:
|
|
if (!(msr & FEAT_CTL_SGX_ENABLED)) {
|
|
if (enable_sgx_kvm || enable_sgx_driver)
|
|
pr_err_once("SGX disabled by BIOS.\n");
|
|
clear_cpu_cap(c, X86_FEATURE_SGX);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* VMX feature bit may be cleared due to being disabled in BIOS,
|
|
* in which case SGX virtualization cannot be supported either.
|
|
*/
|
|
if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) {
|
|
pr_err_once("SGX virtualization disabled due to lack of VMX.\n");
|
|
enable_sgx_kvm = 0;
|
|
}
|
|
|
|
if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) {
|
|
if (!enable_sgx_kvm) {
|
|
pr_err_once("SGX Launch Control is locked. Disable SGX.\n");
|
|
clear_cpu_cap(c, X86_FEATURE_SGX);
|
|
} else {
|
|
pr_err_once("SGX Launch Control is locked. Support SGX virtualization only.\n");
|
|
clear_cpu_cap(c, X86_FEATURE_SGX_LC);
|
|
}
|
|
}
|
|
}
|