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    Subject[PATCH RFC v7 36/64] KVM: SVM: Add initial SEV-SNP support
    Date
    From: Brijesh Singh <brijesh.singh@amd.com>

    The next generation of SEV is called SEV-SNP (Secure Nested Paging).
    SEV-SNP builds upon existing SEV and SEV-ES functionality while adding new
    hardware based security protection. SEV-SNP adds strong memory encryption
    integrity protection to help prevent malicious hypervisor-based attacks
    such as data replay, memory re-mapping, and more, to create an isolated
    execution environment.

    The SNP feature is added incrementally, the later patches adds a new module
    parameters that can be used to enabled SEV-SNP in the KVM.

    Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
    Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
    Signed-off-by: Michael Roth <michael.roth@amd.com>
    ---
    arch/x86/kvm/svm/sev.c | 10 +++++++++-
    arch/x86/kvm/svm/svm.h | 8 ++++++++
    2 files changed, 17 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
    index 0e93b536dc34..f34da1203e09 100644
    --- a/arch/x86/kvm/svm/sev.c
    +++ b/arch/x86/kvm/svm/sev.c
    @@ -57,6 +57,9 @@ module_param_named(sev_es, sev_es_enabled, bool, 0444);
    #define sev_es_enabled false
    #endif /* CONFIG_KVM_AMD_SEV */

    +/* enable/disable SEV-SNP support */
    +static bool sev_snp_enabled;
    +
    #define AP_RESET_HOLD_NONE 0
    #define AP_RESET_HOLD_NAE_EVENT 1
    #define AP_RESET_HOLD_MSR_PROTO 2
    @@ -2298,6 +2301,7 @@ void __init sev_hardware_setup(void)
    {
    #ifdef CONFIG_KVM_AMD_SEV
    unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
    + bool sev_snp_supported = false;
    bool sev_es_supported = false;
    bool sev_supported = false;

    @@ -2377,12 +2381,16 @@ void __init sev_hardware_setup(void)
    if (misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count))
    goto out;

    - pr_info("SEV-ES supported: %u ASIDs\n", sev_es_asid_count);
    sev_es_supported = true;
    + sev_snp_supported = sev_snp_enabled && cpu_feature_enabled(X86_FEATURE_SEV_SNP);
    +
    + pr_info("SEV-ES %ssupported: %u ASIDs\n",
    + sev_snp_supported ? "and SEV-SNP " : "", sev_es_asid_count);

    out:
    sev_enabled = sev_supported;
    sev_es_enabled = sev_es_supported;
    + sev_snp_enabled = sev_snp_supported;
    #endif
    }

    diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
    index ea9844546e8a..a48fe5d2bea5 100644
    --- a/arch/x86/kvm/svm/svm.h
    +++ b/arch/x86/kvm/svm/svm.h
    @@ -83,6 +83,7 @@ enum {
    struct kvm_sev_info {
    bool active; /* SEV enabled guest */
    bool es_active; /* SEV-ES enabled guest */
    + bool snp_active; /* SEV-SNP enabled guest */
    unsigned int asid; /* ASID used for this guest */
    unsigned int handle; /* SEV firmware handle */
    int fd; /* SEV device fd */
    @@ -330,6 +331,13 @@ static __always_inline bool sev_es_guest(struct kvm *kvm)
    #endif
    }

    +static inline bool sev_snp_guest(struct kvm *kvm)
    +{
    + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
    +
    + return sev_es_guest(kvm) && sev->snp_active;
    +}
    +
    static inline void vmcb_mark_all_dirty(struct vmcb *vmcb)
    {
    vmcb->control.clean = 0;
    --
    2.25.1
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