[PATCH 04/18] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

From: Marc Zyngier <maz@kernel.org>
To: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Cc: Alexandru Elisei <alexandru.elisei@arm.com>,
	Andre Przywara <andre.przywara@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Zenghui Yu <yuzenghui@huawei.com>
Subject: [PATCH 04/18] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set
Date: Thu,  9 Feb 2023 17:58:06 +0000	[thread overview]
Message-ID: <20230209175820.1939006-5-maz@kernel.org> (raw)
In-Reply-To: <20230209175820.1939006-1-maz@kernel.org>

From: Christoffer Dall <christoffer.dall@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@armlinux.org.uk>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
[maz: rework register reset not to use empty data structures]
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/reset.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index e0267f672b8a..d061dcc21578 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)
 
@@ -220,6 +224,10 @@ static int kvm_set_vm_width(struct kvm_vcpu *vcpu)
 	if (kvm_has_mte(kvm) && is32bit)
 		return -EINVAL;
 
+	/* NV is incompatible with AArch32 */
+	if (vcpu_has_nv(vcpu) && is32bit)
+		return -EINVAL;
+
 	if (is32bit)
 		set_bit(KVM_ARCH_FLAG_EL1_32BIT, &kvm->arch.flags);
 
@@ -272,6 +280,12 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	if (loaded)
 		kvm_arch_vcpu_put(vcpu);
 
+	/* Disallow NV+SVE for the time being */
+	if (vcpu_has_nv(vcpu) && vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
 		if (test_bit(KVM_ARM_VCPU_SVE, vcpu->arch.features)) {
 			ret = kvm_vcpu_enable_sve(vcpu);
@@ -294,6 +308,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 	default:
 		if (vcpu_el1_is_32bit(vcpu)) {
 			pstate = VCPU_RESET_PSTATE_SVC;
+		} else if (vcpu_has_nv(vcpu)) {
+			pstate = VCPU_RESET_PSTATE_EL2;
 		} else {
 			pstate = VCPU_RESET_PSTATE_EL1;
 		}
-- 
2.34.1

