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Diffstat (limited to 'arch/x86/kvm/svm/sev.c')
-rw-r--r--arch/x86/kvm/svm/sev.c100
1 files changed, 83 insertions, 17 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index d3aec1f2cad2..b9a0a939d59f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -23,6 +23,7 @@
#include <asm/pkru.h>
#include <asm/trapnr.h>
#include <asm/fpu/xcr.h>
+#include <asm/debugreg.h>
#include "mmu.h"
#include "x86.h"
@@ -54,9 +55,14 @@ module_param_named(sev, sev_enabled, bool, 0444);
/* enable/disable SEV-ES support */
static bool sev_es_enabled = true;
module_param_named(sev_es, sev_es_enabled, bool, 0444);
+
+/* enable/disable SEV-ES DebugSwap support */
+static bool sev_es_debug_swap_enabled = true;
+module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
#else
#define sev_enabled false
#define sev_es_enabled false
+#define sev_es_debug_swap_enabled false
#endif /* CONFIG_KVM_AMD_SEV */
static u8 sev_enc_bit;
@@ -606,6 +612,9 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
save->xss = svm->vcpu.arch.ia32_xss;
save->dr6 = svm->vcpu.arch.dr6;
+ if (sev_es_debug_swap_enabled)
+ save->sev_features |= SVM_SEV_FEAT_DEBUG_SWAP;
+
pr_debug("Virtual Machine Save Area (VMSA):\n");
print_hex_dump_debug("", DUMP_PREFIX_NONE, 16, 1, save, sizeof(*save), false);
@@ -619,6 +628,11 @@ static int __sev_launch_update_vmsa(struct kvm *kvm, struct kvm_vcpu *vcpu,
struct vcpu_svm *svm = to_svm(vcpu);
int ret;
+ if (vcpu->guest_debug) {
+ pr_warn_once("KVM_SET_GUEST_DEBUG for SEV-ES guest is not supported");
+ return -EINVAL;
+ }
+
/* Perform some pre-encryption checks against the VMSA */
ret = sev_es_sync_vmsa(svm);
if (ret)
@@ -1725,7 +1739,7 @@ static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm)
* Note, the source is not required to have the same number of
* vCPUs as the destination when migrating a vanilla SEV VM.
*/
- src_vcpu = kvm_get_vcpu(dst_kvm, i);
+ src_vcpu = kvm_get_vcpu(src_kvm, i);
src_svm = to_svm(src_vcpu);
/*
@@ -2171,7 +2185,7 @@ void __init sev_hardware_setup(void)
bool sev_es_supported = false;
bool sev_supported = false;
- if (!sev_enabled || !npt_enabled)
+ if (!sev_enabled || !npt_enabled || !nrips)
goto out;
/*
@@ -2256,6 +2270,9 @@ out:
sev_enabled = sev_supported;
sev_es_enabled = sev_es_supported;
+ if (!sev_es_enabled || !cpu_feature_enabled(X86_FEATURE_DEBUG_SWAP) ||
+ !cpu_feature_enabled(X86_FEATURE_NO_NESTED_DATA_BP))
+ sev_es_debug_swap_enabled = false;
#endif
}
@@ -2881,7 +2898,10 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
svm->sev_es.ghcb_sa);
break;
case SVM_VMGEXIT_NMI_COMPLETE:
- ret = svm_invoke_exit_handler(vcpu, SVM_EXIT_IRET);
+ ++vcpu->stat.nmi_window_exits;
+ svm->nmi_masked = false;
+ kvm_make_request(KVM_REQ_EVENT, vcpu);
+ ret = 1;
break;
case SVM_VMGEXIT_AP_HLT_LOOP:
ret = kvm_emulate_ap_reset_hold(vcpu);
@@ -2944,6 +2964,7 @@ int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
static void sev_es_init_vmcb(struct vcpu_svm *svm)
{
+ struct vmcb *vmcb = svm->vmcb01.ptr;
struct kvm_vcpu *vcpu = &svm->vcpu;
svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ES_ENABLE;
@@ -2952,9 +2973,12 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
/*
* An SEV-ES guest requires a VMSA area that is a separate from the
* VMCB page. Do not include the encryption mask on the VMSA physical
- * address since hardware will access it using the guest key.
+ * address since hardware will access it using the guest key. Note,
+ * the VMSA will be NULL if this vCPU is the destination for intrahost
+ * migration, and will be copied later.
*/
- svm->vmcb->control.vmsa_pa = __pa(svm->sev_es.vmsa);
+ if (svm->sev_es.vmsa)
+ svm->vmcb->control.vmsa_pa = __pa(svm->sev_es.vmsa);
/* Can't intercept CR register access, HV can't modify CR registers */
svm_clr_intercept(svm, INTERCEPT_CR0_READ);
@@ -2972,8 +2996,23 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm)
svm_set_intercept(svm, TRAP_CR4_WRITE);
svm_set_intercept(svm, TRAP_CR8_WRITE);
- /* No support for enable_vmware_backdoor */
- clr_exception_intercept(svm, GP_VECTOR);
+ vmcb->control.intercepts[INTERCEPT_DR] = 0;
+ if (!sev_es_debug_swap_enabled) {
+ vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_READ);
+ vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_WRITE);
+ recalc_intercepts(svm);
+ } else {
+ /*
+ * Disable #DB intercept iff DebugSwap is enabled. KVM doesn't
+ * allow debugging SEV-ES guests, and enables DebugSwap iff
+ * NO_NESTED_DATA_BP is supported, so there's no reason to
+ * intercept #DB when DebugSwap is enabled. For simplicity
+ * with respect to guest debug, intercept #DB for other VMs
+ * even if NO_NESTED_DATA_BP is supported, i.e. even if the
+ * guest can't DoS the CPU with infinite #DB vectoring.
+ */
+ clr_exception_intercept(svm, DB_VECTOR);
+ }
/* Can't intercept XSETBV, HV can't modify XCR0 directly */
svm_clr_intercept(svm, INTERCEPT_XSETBV);
@@ -3000,6 +3039,12 @@ void sev_init_vmcb(struct vcpu_svm *svm)
svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ENABLE;
clr_exception_intercept(svm, UD_VECTOR);
+ /*
+ * Don't intercept #GP for SEV guests, e.g. for the VMware backdoor, as
+ * KVM can't decrypt guest memory to decode the faulting instruction.
+ */
+ clr_exception_intercept(svm, GP_VECTOR);
+
if (sev_es_guest(svm->vcpu.kvm))
sev_es_init_vmcb(svm);
}
@@ -3018,20 +3063,41 @@ void sev_es_vcpu_reset(struct vcpu_svm *svm)
void sev_es_prepare_switch_to_guest(struct sev_es_save_area *hostsa)
{
/*
- * As an SEV-ES guest, hardware will restore the host state on VMEXIT,
- * of which one step is to perform a VMLOAD. KVM performs the
- * corresponding VMSAVE in svm_prepare_guest_switch for both
- * traditional and SEV-ES guests.
+ * All host state for SEV-ES guests is categorized into three swap types
+ * based on how it is handled by hardware during a world switch:
+ *
+ * A: VMRUN: Host state saved in host save area
+ * VMEXIT: Host state loaded from host save area
+ *
+ * B: VMRUN: Host state _NOT_ saved in host save area
+ * VMEXIT: Host state loaded from host save area
+ *
+ * C: VMRUN: Host state _NOT_ saved in host save area
+ * VMEXIT: Host state initialized to default(reset) values
+ *
+ * Manually save type-B state, i.e. state that is loaded by VMEXIT but
+ * isn't saved by VMRUN, that isn't already saved by VMSAVE (performed
+ * by common SVM code).
*/
-
- /* XCR0 is restored on VMEXIT, save the current host value */
hostsa->xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
-
- /* PKRU is restored on VMEXIT, save the current host value */
hostsa->pkru = read_pkru();
-
- /* MSR_IA32_XSS is restored on VMEXIT, save the currnet host value */
hostsa->xss = host_xss;
+
+ /*
+ * If DebugSwap is enabled, debug registers are loaded but NOT saved by
+ * the CPU (Type-B). If DebugSwap is disabled/unsupported, the CPU both
+ * saves and loads debug registers (Type-A).
+ */
+ if (sev_es_debug_swap_enabled) {
+ hostsa->dr0 = native_get_debugreg(0);
+ hostsa->dr1 = native_get_debugreg(1);
+ hostsa->dr2 = native_get_debugreg(2);
+ hostsa->dr3 = native_get_debugreg(3);
+ hostsa->dr0_addr_mask = amd_get_dr_addr_mask(0);
+ hostsa->dr1_addr_mask = amd_get_dr_addr_mask(1);
+ hostsa->dr2_addr_mask = amd_get_dr_addr_mask(2);
+ hostsa->dr3_addr_mask = amd_get_dr_addr_mask(3);
+ }
}
void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-26 06:43:40 +0000