[Part2 PATCH v6 05/38] KVM: SVM: Prepare to reserve asid for SEV guest

[Brijesh Singh]

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

Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: "Radim Krčmář" <rkrc...@redhat.com>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Borislav Petkov <b...@suse.de>
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: x...@kernel.org
Cc: k...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Borislav Petkov <b...@suse.de>
---
 arch/x86/kvm/svm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8186b8d7c469..2c3a3c88596c 100644
--- 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);
@@ -2091,7 +2093,7 @@ 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;
        }
 
-- 
2.9.5