[RFC PATCH v2 22/32] kvm: svm: prepare to reserve asid for SEV guest

[Brijesh Singh <brijesh.singh@amd.com>]

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

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 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 b581499..8d8fe62 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -507,6 +507,7 @@ 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;
@@ -763,6 +764,7 @@ 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;
 
 	native_store_gdt(&gdt_descr);
 	gdt = (struct desc_struct *)gdt_descr.address;
@@ -2026,7 +2028,7 @@ 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;
 	}