arm64: KVM: Add support for 16-bit VMID

The ARMv8.1 architecture extension allows to choose between 8-bit and
16-bit of VMID, so use this capability for KVM.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 6e35d1d7893e..f6bcc2e4a133 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -59,7 +59,8 @@ static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
 
 /* The VMID used in the VTTBR */
 static atomic64_t kvm_vmid_gen = ATOMIC64_INIT(1);
-static u8 kvm_next_vmid;
+static u32 kvm_next_vmid;
+static unsigned int kvm_vmid_bits __read_mostly;
 static DEFINE_SPINLOCK(kvm_vmid_lock);
 
 static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
@@ -434,11 +435,12 @@ static void update_vttbr(struct kvm *kvm)
         kvm->arch.vmid_gen = atomic64_read(&kvm_vmid_gen);
         kvm->arch.vmid = kvm_next_vmid;
         kvm_next_vmid++;
+        kvm_next_vmid &= (1 << kvm_vmid_bits) - 1;
 
         /* update vttbr to be used with the new vmid */
         pgd_phys = virt_to_phys(kvm_get_hwpgd(kvm));
         BUG_ON(pgd_phys & ~VTTBR_BADDR_MASK);
-        vmid = ((u64)(kvm->arch.vmid) << VTTBR_VMID_SHIFT) & VTTBR_VMID_MASK;
+        vmid = ((u64)(kvm->arch.vmid) << VTTBR_VMID_SHIFT) & VTTBR_VMID_MASK(kvm_vmid_bits);
         kvm->arch.vttbr = pgd_phys | vmid;
 
         spin_unlock(&kvm_vmid_lock);
@@ -1135,6 +1137,10 @@ static int init_hyp_mode(void)
 
         kvm_perf_init();
 
+        /* set size of VMID supported by CPU */
+        kvm_vmid_bits = kvm_get_vmid_bits();
+        kvm_info("%d-bit VMID\n", kvm_vmid_bits);
+
         kvm_info("Hyp mode initialized successfully\n");
 
         return 0;