diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index f8192864b496..24d1fb29ea2e 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -11,6 +11,8 @@ #define PT32_PT_BITS 10 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS) +extern bool __read_mostly enable_mmio_caching; + #define PT_WRITABLE_SHIFT 1 #define PT_USER_SHIFT 2 diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index b5960bbde7f7..dfdc727a12ad 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -21,6 +21,7 @@ bool __read_mostly enable_mmio_caching = true; module_param_named(mmio_caching, enable_mmio_caching, bool, 0444); +EXPORT_SYMBOL_GPL(enable_mmio_caching); u64 __read_mostly shadow_host_writable_mask; u64 __read_mostly shadow_mmu_writable_mask; diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 0127bb6e3c7d..7f0af695fd38 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -5,8 +5,6 @@ #include "mmu_internal.h" -extern bool __read_mostly enable_mmio_caching; - /* * A MMU present SPTE is backed by actual memory and may or may not be present * in hardware. E.g. MMIO SPTEs are not considered present. Use bit 11, as it diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 0c240ed04f96..eb7a088a80a4 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -22,6 +22,7 @@ #include #include +#include "mmu.h" #include "x86.h" #include "svm.h" #include "svm_ops.h" @@ -2221,6 +2222,15 @@ void __init sev_hardware_setup(void) if (!sev_es_enabled) goto out; + /* + * SEV-ES requires MMIO caching as KVM doesn't have access to the guest + * instruction stream, i.e. can't emulate in response to a #NPF and + * instead relies on #NPF(RSVD) being reflected into the guest as #VC + * (the guest can then do a #VMGEXIT to request MMIO emulation). + */ + if (!enable_mmio_caching) + goto out; + /* Does the CPU support SEV-ES? */ if (!boot_cpu_has(X86_FEATURE_SEV_ES)) goto out; diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e9f479acf941..40e560c875f1 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4897,13 +4897,16 @@ static __init int svm_hardware_setup(void) /* Setup shadow_me_value and shadow_me_mask */ kvm_mmu_set_me_spte_mask(sme_me_mask, sme_me_mask); - /* Note, SEV setup consumes npt_enabled. */ + svm_adjust_mmio_mask(); + + /* + * Note, SEV setup consumes npt_enabled and enable_mmio_caching (which + * may be modified by svm_adjust_mmio_mask()). + */ sev_hardware_setup(); svm_hv_hardware_setup(); - svm_adjust_mmio_mask(); - for_each_possible_cpu(cpu) { r = svm_cpu_init(cpu); if (r)