[Part2 PATCH v4 08/29] KVM: SVM: Prepare to reserve asid for SEV guest

[Brijesh Singh]

In current implementation, asid allocation starts from 1, adds a
min_asid variable in svm_vcpu structure to allow starting asid from
something other than 1.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim KrÄmÃÅ" <rkrcmar@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
 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