diff options
author | Paolo Bonzini <pbonzini@redhat.com> | 2023-08-31 20:36:33 +0300 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-08-31 20:36:33 +0300 |
commit | 6d5e3c318a33edb1f9176964c4ed7f076fc4248c (patch) | |
tree | 0af8c82dd29310f3d8b8bceb9107227b3b03495f /arch/x86/kvm/vmx/vmx.c | |
parent | bd7fe98b353b7e52b3db239d86cbe04234097a20 (diff) | |
parent | 9717efbe5ba3f52d4b3cc637c7f7f6149ea264bb (diff) | |
download | linux-6d5e3c318a33edb1f9176964c4ed7f076fc4248c.tar.xz |
Merge tag 'kvm-x86-misc-6.6' of https://github.com/kvm-x86/linux into HEAD
KVM x86 changes for 6.6:
- Misc cleanups
- Retry APIC optimized recalculation if a vCPU is added/enabled
- Overhaul emergency reboot code to bring SVM up to par with VMX, tie the
"emergency disabling" behavior to KVM actually being loaded, and move all of
the logic within KVM
- Fix user triggerable WARNs in SVM where KVM incorrectly assumes the TSC
ratio MSR can diverge from the default iff TSC scaling is enabled, and clean
up related code
- Add a framework to allow "caching" feature flags so that KVM can check if
the guest can use a feature without needing to search guest CPUID
Diffstat (limited to 'arch/x86/kvm/vmx/vmx.c')
-rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 190 |
1 files changed, 99 insertions, 91 deletions
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index c0236dd4d892..af73d5d54ec8 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -41,13 +41,12 @@ #include <asm/idtentry.h> #include <asm/io.h> #include <asm/irq_remapping.h> -#include <asm/kexec.h> +#include <asm/reboot.h> #include <asm/perf_event.h> #include <asm/mmu_context.h> #include <asm/mshyperv.h> #include <asm/mwait.h> #include <asm/spec-ctrl.h> -#include <asm/virtext.h> #include <asm/vmx.h> #include "capabilities.h" @@ -237,9 +236,6 @@ static const struct { #define L1D_CACHE_ORDER 4 static void *vmx_l1d_flush_pages; -/* Control for disabling CPU Fill buffer clear */ -static bool __read_mostly vmx_fb_clear_ctrl_available; - static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) { struct page *page; @@ -255,14 +251,9 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) return 0; } - if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) { - u64 msr; - - rdmsrl(MSR_IA32_ARCH_CAPABILITIES, msr); - if (msr & ARCH_CAP_SKIP_VMENTRY_L1DFLUSH) { - l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED; - return 0; - } + if (host_arch_capabilities & ARCH_CAP_SKIP_VMENTRY_L1DFLUSH) { + l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED; + return 0; } /* If set to auto use the default l1tf mitigation method */ @@ -366,22 +357,9 @@ static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp) static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp) { if (WARN_ON_ONCE(l1tf_vmx_mitigation >= ARRAY_SIZE(vmentry_l1d_param))) - return sprintf(s, "???\n"); + return sysfs_emit(s, "???\n"); - return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option); -} - -static void vmx_setup_fb_clear_ctrl(void) -{ - u64 msr; - - if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES) && - !boot_cpu_has_bug(X86_BUG_MDS) && - !boot_cpu_has_bug(X86_BUG_TAA)) { - rdmsrl(MSR_IA32_ARCH_CAPABILITIES, msr); - if (msr & ARCH_CAP_FB_CLEAR_CTRL) - vmx_fb_clear_ctrl_available = true; - } + return sysfs_emit(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option); } static __always_inline void vmx_disable_fb_clear(struct vcpu_vmx *vmx) @@ -409,7 +387,9 @@ static __always_inline void vmx_enable_fb_clear(struct vcpu_vmx *vmx) static void vmx_update_fb_clear_dis(struct kvm_vcpu *vcpu, struct vcpu_vmx *vmx) { - vmx->disable_fb_clear = vmx_fb_clear_ctrl_available; + vmx->disable_fb_clear = (host_arch_capabilities & ARCH_CAP_FB_CLEAR_CTRL) && + !boot_cpu_has_bug(X86_BUG_MDS) && + !boot_cpu_has_bug(X86_BUG_TAA); /* * If guest will not execute VERW, there is no need to set FB_CLEAR_DIS @@ -754,17 +734,51 @@ static int vmx_set_guest_uret_msr(struct vcpu_vmx *vmx, return ret; } -#ifdef CONFIG_KEXEC_CORE -static void crash_vmclear_local_loaded_vmcss(void) +/* + * Disable VMX and clear CR4.VMXE (even if VMXOFF faults) + * + * Note, VMXOFF causes a #UD if the CPU is !post-VMXON, but it's impossible to + * atomically track post-VMXON state, e.g. this may be called in NMI context. + * Eat all faults as all other faults on VMXOFF faults are mode related, i.e. + * faults are guaranteed to be due to the !post-VMXON check unless the CPU is + * magically in RM, VM86, compat mode, or at CPL>0. + */ +static int kvm_cpu_vmxoff(void) +{ + asm_volatile_goto("1: vmxoff\n\t" + _ASM_EXTABLE(1b, %l[fault]) + ::: "cc", "memory" : fault); + + cr4_clear_bits(X86_CR4_VMXE); + return 0; + +fault: + cr4_clear_bits(X86_CR4_VMXE); + return -EIO; +} + +static void vmx_emergency_disable(void) { int cpu = raw_smp_processor_id(); struct loaded_vmcs *v; + kvm_rebooting = true; + + /* + * Note, CR4.VMXE can be _cleared_ in NMI context, but it can only be + * set in task context. If this races with VMX is disabled by an NMI, + * VMCLEAR and VMXOFF may #UD, but KVM will eat those faults due to + * kvm_rebooting set. + */ + if (!(__read_cr4() & X86_CR4_VMXE)) + return; + list_for_each_entry(v, &per_cpu(loaded_vmcss_on_cpu, cpu), loaded_vmcss_on_cpu_link) vmcs_clear(v->vmcs); + + kvm_cpu_vmxoff(); } -#endif /* CONFIG_KEXEC_CORE */ static void __loaded_vmcs_clear(void *arg) { @@ -1899,25 +1913,14 @@ u64 vmx_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu) return kvm_caps.default_tsc_scaling_ratio; } -static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) -{ - vmcs_write64(TSC_OFFSET, offset); -} - -static void vmx_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier) +static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu) { - vmcs_write64(TSC_MULTIPLIER, multiplier); + vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset); } -/* - * nested_vmx_allowed() checks whether a guest should be allowed to use VMX - * instructions and MSRs (i.e., nested VMX). Nested VMX is disabled for - * all guests if the "nested" module option is off, and can also be disabled - * for a single guest by disabling its VMX cpuid bit. - */ -bool nested_vmx_allowed(struct kvm_vcpu *vcpu) +static void vmx_write_tsc_multiplier(struct kvm_vcpu *vcpu) { - return nested && guest_cpuid_has(vcpu, X86_FEATURE_VMX); + vmcs_write64(TSC_MULTIPLIER, vcpu->arch.tsc_scaling_ratio); } /* @@ -2047,7 +2050,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) [msr_info->index - MSR_IA32_SGXLEPUBKEYHASH0]; break; case KVM_FIRST_EMULATED_VMX_MSR ... KVM_LAST_EMULATED_VMX_MSR: - if (!nested_vmx_allowed(vcpu)) + if (!guest_can_use(vcpu, X86_FEATURE_VMX)) return 1; if (vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index, &msr_info->data)) @@ -2355,7 +2358,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case KVM_FIRST_EMULATED_VMX_MSR ... KVM_LAST_EMULATED_VMX_MSR: if (!msr_info->host_initiated) return 1; /* they are read-only */ - if (!nested_vmx_allowed(vcpu)) + if (!guest_can_use(vcpu, X86_FEATURE_VMX)) return 1; return vmx_set_vmx_msr(vcpu, msr_index, data); case MSR_IA32_RTIT_CTL: @@ -2729,11 +2732,11 @@ static int setup_vmcs_config(struct vmcs_config *vmcs_conf, return 0; } -static bool kvm_is_vmx_supported(void) +static bool __kvm_is_vmx_supported(void) { - int cpu = raw_smp_processor_id(); + int cpu = smp_processor_id(); - if (!cpu_has_vmx()) { + if (!(cpuid_ecx(1) & feature_bit(VMX))) { pr_err("VMX not supported by CPU %d\n", cpu); return false; } @@ -2747,13 +2750,24 @@ static bool kvm_is_vmx_supported(void) return true; } +static bool kvm_is_vmx_supported(void) +{ + bool supported; + + migrate_disable(); + supported = __kvm_is_vmx_supported(); + migrate_enable(); + + return supported; +} + static int vmx_check_processor_compat(void) { int cpu = raw_smp_processor_id(); struct vmcs_config vmcs_conf; struct vmx_capability vmx_cap; - if (!kvm_is_vmx_supported()) + if (!__kvm_is_vmx_supported()) return -EIO; if (setup_vmcs_config(&vmcs_conf, &vmx_cap) < 0) { @@ -2833,7 +2847,7 @@ static void vmx_hardware_disable(void) { vmclear_local_loaded_vmcss(); - if (cpu_vmxoff()) + if (kvm_cpu_vmxoff()) kvm_spurious_fault(); hv_reset_evmcs(); @@ -4546,16 +4560,19 @@ vmx_adjust_secondary_exec_control(struct vcpu_vmx *vmx, u32 *exec_control, * based on a single guest CPUID bit, with a dedicated feature bit. This also * verifies that the control is actually supported by KVM and hardware. */ -#define vmx_adjust_sec_exec_control(vmx, exec_control, name, feat_name, ctrl_name, exiting) \ -({ \ - bool __enabled; \ - \ - if (cpu_has_vmx_##name()) { \ - __enabled = guest_cpuid_has(&(vmx)->vcpu, \ - X86_FEATURE_##feat_name); \ - vmx_adjust_secondary_exec_control(vmx, exec_control, \ - SECONDARY_EXEC_##ctrl_name, __enabled, exiting); \ - } \ +#define vmx_adjust_sec_exec_control(vmx, exec_control, name, feat_name, ctrl_name, exiting) \ +({ \ + struct kvm_vcpu *__vcpu = &(vmx)->vcpu; \ + bool __enabled; \ + \ + if (cpu_has_vmx_##name()) { \ + if (kvm_is_governed_feature(X86_FEATURE_##feat_name)) \ + __enabled = guest_can_use(__vcpu, X86_FEATURE_##feat_name); \ + else \ + __enabled = guest_cpuid_has(__vcpu, X86_FEATURE_##feat_name); \ + vmx_adjust_secondary_exec_control(vmx, exec_control, SECONDARY_EXEC_##ctrl_name,\ + __enabled, exiting); \ + } \ }) /* More macro magic for ENABLE_/opt-in versus _EXITING/opt-out controls. */ @@ -4615,19 +4632,7 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx) if (!enable_pml || !atomic_read(&vcpu->kvm->nr_memslots_dirty_logging)) exec_control &= ~SECONDARY_EXEC_ENABLE_PML; - if (cpu_has_vmx_xsaves()) { - /* Exposing XSAVES only when XSAVE is exposed */ - bool xsaves_enabled = - boot_cpu_has(X86_FEATURE_XSAVE) && - guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) && - guest_cpuid_has(vcpu, X86_FEATURE_XSAVES); - - vcpu->arch.xsaves_enabled = xsaves_enabled; - - vmx_adjust_secondary_exec_control(vmx, &exec_control, - SECONDARY_EXEC_XSAVES, - xsaves_enabled, false); - } + vmx_adjust_sec_exec_feature(vmx, &exec_control, xsaves, XSAVES); /* * RDPID is also gated by ENABLE_RDTSCP, turn on the control if either @@ -4646,6 +4651,7 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx) SECONDARY_EXEC_ENABLE_RDTSCP, rdpid_or_rdtscp_enabled, false); } + vmx_adjust_sec_exec_feature(vmx, &exec_control, invpcid, INVPCID); vmx_adjust_sec_exec_exiting(vmx, &exec_control, rdrand, RDRAND); @@ -7747,8 +7753,16 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - /* xsaves_enabled is recomputed in vmx_compute_secondary_exec_control(). */ - vcpu->arch.xsaves_enabled = false; + /* + * XSAVES is effectively enabled if and only if XSAVE is also exposed + * to the guest. XSAVES depends on CR4.OSXSAVE, and CR4.OSXSAVE can be + * set if and only if XSAVE is supported. + */ + if (boot_cpu_has(X86_FEATURE_XSAVE) && + guest_cpuid_has(vcpu, X86_FEATURE_XSAVE)) + kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_XSAVES); + + kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VMX); vmx_setup_uret_msrs(vmx); @@ -7756,7 +7770,7 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) vmcs_set_secondary_exec_control(vmx, vmx_secondary_exec_control(vmx)); - if (nested_vmx_allowed(vcpu)) + if (guest_can_use(vcpu, X86_FEATURE_VMX)) vmx->msr_ia32_feature_control_valid_bits |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX | FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX; @@ -7765,7 +7779,7 @@ static void vmx_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) ~(FEAT_CTL_VMX_ENABLED_INSIDE_SMX | FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX); - if (nested_vmx_allowed(vcpu)) + if (guest_can_use(vcpu, X86_FEATURE_VMX)) nested_vmx_cr_fixed1_bits_update(vcpu); if (boot_cpu_has(X86_FEATURE_INTEL_PT) && @@ -8618,10 +8632,8 @@ static void __vmx_exit(void) { allow_smaller_maxphyaddr = false; -#ifdef CONFIG_KEXEC_CORE - RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); - synchronize_rcu(); -#endif + cpu_emergency_unregister_virt_callback(vmx_emergency_disable); + vmx_cleanup_l1d_flush(); } @@ -8662,18 +8674,14 @@ static int __init vmx_init(void) if (r) goto err_l1d_flush; - vmx_setup_fb_clear_ctrl(); - for_each_possible_cpu(cpu) { INIT_LIST_HEAD(&per_cpu(loaded_vmcss_on_cpu, cpu)); pi_init_cpu(cpu); } -#ifdef CONFIG_KEXEC_CORE - rcu_assign_pointer(crash_vmclear_loaded_vmcss, - crash_vmclear_local_loaded_vmcss); -#endif + cpu_emergency_register_virt_callback(vmx_emergency_disable); + vmx_check_vmcs12_offsets(); /* |