From ff651cb613b4cc8aa2e4284525948872b4d77d66 Mon Sep 17 00:00:00 2001 From: Wincy Van Date: Thu, 11 Dec 2014 08:52:58 +0300 Subject: [PATCH] KVM: nVMX: Add nested msr load/restore algorithm Several hypervisors need MSR auto load/restore feature. We read MSRs from VM-entry MSR load area which specified by L1, and load them via kvm_set_msr in the nested entry. When nested exit occurs, we get MSRs via kvm_get_msr, writing them to L1`s MSR store area. After this, we read MSRs from VM-exit MSR load area, and load them via kvm_set_msr. Signed-off-by: Wincy Van Signed-off-by: Paolo Bonzini --- arch/x86/include/uapi/asm/vmx.h | 5 ++ arch/x86/kvm/vmx.c | 101 ++++++++++++++++++++++++++++---- arch/x86/kvm/x86.c | 1 + virt/kvm/kvm_main.c | 1 + 4 files changed, 97 insertions(+), 11 deletions(-) diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h index b813bf9da1e2..ff2b8e28883e 100644 --- a/arch/x86/include/uapi/asm/vmx.h +++ b/arch/x86/include/uapi/asm/vmx.h @@ -56,6 +56,7 @@ #define EXIT_REASON_MSR_READ 31 #define EXIT_REASON_MSR_WRITE 32 #define EXIT_REASON_INVALID_STATE 33 +#define EXIT_REASON_MSR_LOAD_FAIL 34 #define EXIT_REASON_MWAIT_INSTRUCTION 36 #define EXIT_REASON_MONITOR_INSTRUCTION 39 #define EXIT_REASON_PAUSE_INSTRUCTION 40 @@ -116,10 +117,14 @@ { EXIT_REASON_APIC_WRITE, "APIC_WRITE" }, \ { EXIT_REASON_EOI_INDUCED, "EOI_INDUCED" }, \ { EXIT_REASON_INVALID_STATE, "INVALID_STATE" }, \ + { EXIT_REASON_MSR_LOAD_FAIL, "MSR_LOAD_FAIL" }, \ { EXIT_REASON_INVD, "INVD" }, \ { EXIT_REASON_INVVPID, "INVVPID" }, \ { EXIT_REASON_INVPCID, "INVPCID" }, \ { EXIT_REASON_XSAVES, "XSAVES" }, \ { EXIT_REASON_XRSTORS, "XRSTORS" } +#define VMX_ABORT_SAVE_GUEST_MSR_FAIL 1 +#define VMX_ABORT_LOAD_HOST_MSR_FAIL 4 + #endif /* _UAPIVMX_H */ diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d4c58d884838..9137d2ba26a2 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6143,6 +6143,13 @@ static void nested_vmx_failValid(struct kvm_vcpu *vcpu, */ } +static void nested_vmx_abort(struct kvm_vcpu *vcpu, u32 indicator) +{ + /* TODO: not to reset guest simply here. */ + kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu); + pr_warn("kvm: nested vmx abort, indicator %d\n", indicator); +} + static enum hrtimer_restart vmx_preemption_timer_fn(struct hrtimer *timer) { struct vcpu_vmx *vmx = @@ -8286,6 +8293,67 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu) ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL); } +static inline int nested_vmx_msr_check_common(struct vmx_msr_entry *e) +{ + if (e->index >> 8 == 0x8 || e->reserved != 0) + return -EINVAL; + return 0; +} + +static inline int nested_vmx_load_msr_check(struct vmx_msr_entry *e) +{ + if (e->index == MSR_FS_BASE || + e->index == MSR_GS_BASE || + nested_vmx_msr_check_common(e)) + return -EINVAL; + return 0; +} + +/* + * Load guest's/host's msr at nested entry/exit. + * return 0 for success, entry index for failure. + */ +static u32 nested_vmx_load_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count) +{ + u32 i; + struct vmx_msr_entry e; + struct msr_data msr; + + msr.host_initiated = false; + for (i = 0; i < count; i++) { + kvm_read_guest(vcpu->kvm, gpa + i * sizeof(e), &e, sizeof(e)); + if (nested_vmx_load_msr_check(&e)) + goto fail; + msr.index = e.index; + msr.data = e.value; + if (kvm_set_msr(vcpu, &msr)) + goto fail; + } + return 0; +fail: + return i + 1; +} + +static int nested_vmx_store_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count) +{ + u32 i; + struct vmx_msr_entry e; + + for (i = 0; i < count; i++) { + kvm_read_guest(vcpu->kvm, gpa + i * sizeof(e), + &e, 2 * sizeof(u32)); + if (nested_vmx_msr_check_common(&e)) + return -EINVAL; + if (kvm_get_msr(vcpu, e.index, &e.value)) + return -EINVAL; + kvm_write_guest(vcpu->kvm, + gpa + i * sizeof(e) + + offsetof(struct vmx_msr_entry, value), + &e.value, sizeof(e.value)); + } + return 0; +} + /* * prepare_vmcs02 is called when the L1 guest hypervisor runs its nested * L2 guest. L1 has a vmcs for L2 (vmcs12), and this function "merges" it @@ -8582,6 +8650,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) int cpu; struct loaded_vmcs *vmcs02; bool ia32e; + u32 msr_entry_idx; if (!nested_vmx_check_permission(vcpu) || !nested_vmx_check_vmcs12(vcpu)) @@ -8629,15 +8698,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) return 1; } - if (vmcs12->vm_entry_msr_load_count > 0 || - vmcs12->vm_exit_msr_load_count > 0 || - vmcs12->vm_exit_msr_store_count > 0) { - pr_warn_ratelimited("%s: VMCS MSR_{LOAD,STORE} unsupported\n", - __func__); - nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD); - return 1; - } - if (!vmx_control_verify(vmcs12->cpu_based_vm_exec_control, nested_vmx_true_procbased_ctls_low, nested_vmx_procbased_ctls_high) || @@ -8739,10 +8799,21 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) vmx_segment_cache_clear(vmx); - vmcs12->launch_state = 1; - prepare_vmcs02(vcpu, vmcs12); + msr_entry_idx = nested_vmx_load_msr(vcpu, + vmcs12->vm_entry_msr_load_addr, + vmcs12->vm_entry_msr_load_count); + if (msr_entry_idx) { + leave_guest_mode(vcpu); + vmx_load_vmcs01(vcpu); + nested_vmx_entry_failure(vcpu, vmcs12, + EXIT_REASON_MSR_LOAD_FAIL, msr_entry_idx); + return 1; + } + + vmcs12->launch_state = 1; + if (vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) return kvm_emulate_halt(vcpu); @@ -9172,6 +9243,10 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, kvm_set_dr(vcpu, 7, 0x400); vmcs_write64(GUEST_IA32_DEBUGCTL, 0); + + if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr, + vmcs12->vm_exit_msr_load_count)) + nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_MSR_FAIL); } /* @@ -9193,6 +9268,10 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, prepare_vmcs12(vcpu, vmcs12, exit_reason, exit_intr_info, exit_qualification); + if (nested_vmx_store_msr(vcpu, vmcs12->vm_exit_msr_store_addr, + vmcs12->vm_exit_msr_store_count)) + nested_vmx_abort(vcpu, VMX_ABORT_SAVE_GUEST_MSR_FAIL); + vmx_load_vmcs01(vcpu); if ((exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c259814200bd..af9faed270f1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2324,6 +2324,7 @@ int kvm_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) { return kvm_x86_ops->get_msr(vcpu, msr_index, pdata); } +EXPORT_SYMBOL_GPL(kvm_get_msr); static int get_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 1cc6e2e19982..167e8c14b143 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1593,6 +1593,7 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data, } return 0; } +EXPORT_SYMBOL_GPL(kvm_write_guest); int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc, gpa_t gpa, unsigned long len) -- 2.20.1