KVM: SVM: Prepare to reserve asid for SEV guest

Currently, ASID allocation start at 1. Add a svm_vcpu_data.min_asid
which allows supplying a dynamic start ASID.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Borislav Petkov <bp@suse.de>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1c8158a6ee06b9d6da94d92b3179e4a6205b6775..e403cf1f6ba3d3c350849808a67b0a670e59fcf0 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -525,6 +525,7 @@ struct svm_cpu_data {
        u64 asid_generation;
        u32 max_asid;
        u32 next_asid;
+       u32 min_asid;
        struct kvm_ldttss_desc *tss_desc;
 
        struct page *save_area;
@@ -782,6 +783,7 @@ static int svm_hardware_enable(void)
        sd->asid_generation = 1;
        sd->max_asid = cpuid_ebx(SVM_CPUID_FUNC) - 1;
        sd->next_asid = sd->max_asid + 1;
+       sd->min_asid = 1;
 
        gdt = get_current_gdt_rw();
        sd->tss_desc = (struct kvm_ldttss_desc *)(gdt + GDT_ENTRY_TSS);
@@ -2088,7 +2090,7 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd)
 {
        if (sd->next_asid > sd->max_asid) {
                ++sd->asid_generation;
-               sd->next_asid = 1;
+               sd->next_asid = sd->min_asid;
                svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ALL_ASID;
        }