[PATCH v6 03/64] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

[Marc Zyngier]

From: Christoffer Dall <christoffer.dall at arm.com>

Reset the VCPU with PSTATE.M = EL2h when the nested virtualization
feature is enabled on the VCPU.

Reviewed-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
Signed-off-by: Christoffer Dall <christoffer.dall at arm.com>
[maz: rework register reset not to use empty data structures]
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/reset.c | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index ecc40c8cd6f6..d19a9aad2d85 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -27,6 +27,7 @@
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
 #include <asm/virt.h>
 
 /* Maximum phys_shift supported for any VM on this host */
@@ -38,6 +39,9 @@ static u32 kvm_ipa_limit;
 #define VCPU_RESET_PSTATE_EL1	(PSR_MODE_EL1h | PSR_A_BIT | PSR_I_BIT | \
 				 PSR_F_BIT | PSR_D_BIT)
 
+#define VCPU_RESET_PSTATE_EL2	(PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT | \
+				 PSR_F_BIT | PSR_D_BIT)
+
 #define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
 				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)
 
@@ -188,12 +192,19 @@ static bool vcpu_allowed_register_width(struct kvm_vcpu *vcpu)
 	unsigned long i;
 
 	is32bit = vcpu_has_feature(vcpu, KVM_ARM_VCPU_EL1_32BIT);
-	if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1) && is32bit)
-		return false;
+	if (is32bit) {
+		/* The HW must obviously support AArch32 at EL1 */
+		if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1))
+			return false;
 
-	/* MTE is incompatible with AArch32 */
-	if (kvm_has_mte(vcpu->kvm) && is32bit)
-		return false;
+		/* MTE is incompatible with AArch32 */
+		if (kvm_has_mte(vcpu->kvm))
+			return false;
+
+		/* NV is incompatible with AArch32 */
+		if (vcpu_has_nv(vcpu))
+			return false;
+	}
 
 	/* Check that the vcpus are either all 32bit or all 64bit */
 	kvm_for_each_vcpu(i, tmp, vcpu->kvm) {
@@ -265,10 +276,18 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 		goto out;
 	}
 
+	if (vcpu_has_nv(vcpu) &&
+	    vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	switch (vcpu->arch.target) {
 	default:
 		if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
 			pstate = VCPU_RESET_PSTATE_SVC;
+		} else if (vcpu_has_nv(vcpu)) {
+			pstate = VCPU_RESET_PSTATE_EL2;
 		} else {
 			pstate = VCPU_RESET_PSTATE_EL1;
 		}
-- 
2.30.2