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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 03/18] KVM: arm64: nv: Introduce nested virtualization VCPU feature
Date: Thu,  9 Feb 2023 17:58:05 +0000	[thread overview]
Message-ID: <20230209175820.1939006-4-maz@kernel.org> (raw)
In-Reply-To: <20230209175820.1939006-1-maz@kernel.org>

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

Introduce the feature bit and a primitive that checks if the feature is
set behind a static key check based on the cpus_have_const_cap check.

Checking vcpu_has_nv() on systems without nested virt enabled
should have negligible overhead.

We don't yet allow userspace to actually set this feature.

Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/kvm_nested.h | 14 ++++++++++++++
 arch/arm64/include/uapi/asm/kvm.h   |  1 +
 2 files changed, 15 insertions(+)
 create mode 100644 arch/arm64/include/asm/kvm_nested.h

diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
new file mode 100644
index 000000000000..fd601ea68d13
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ARM64_KVM_NESTED_H
+#define __ARM64_KVM_NESTED_H
+
+#include <linux/kvm_host.h>
+
+static inline bool vcpu_has_nv(const struct kvm_vcpu *vcpu)
+{
+	return (!__is_defined(__KVM_NVHE_HYPERVISOR__) &&
+		cpus_have_final_cap(ARM64_HAS_NESTED_VIRT) &&
+		test_bit(KVM_ARM_VCPU_HAS_EL2, vcpu->arch.features));
+}
+
+#endif /* __ARM64_KVM_NESTED_H */
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index a7a857f1784d..f8129c624b07 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -109,6 +109,7 @@ struct kvm_regs {
 #define KVM_ARM_VCPU_SVE		4 /* enable SVE for this CPU */
 #define KVM_ARM_VCPU_PTRAUTH_ADDRESS	5 /* VCPU uses address authentication */
 #define KVM_ARM_VCPU_PTRAUTH_GENERIC	6 /* VCPU uses generic authentication */
+#define KVM_ARM_VCPU_HAS_EL2		7 /* Support nested virtualization */
 
 struct kvm_vcpu_init {
 	__u32 target;
-- 
2.34.1


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  parent reply	other threads:[~2023-02-09 18:01 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-09 17:58 [PATCH 00/18] KVM: arm64: Prefix patches for NV support Marc Zyngier
2023-02-09 17:58 ` [PATCH 01/18] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature Marc Zyngier
2023-02-09 17:58 ` [PATCH 02/18] KVM: arm64: Use the S2 MMU context to iterate over S2 table Marc Zyngier
2023-02-11  1:00   ` Andre Przywara
2023-02-09 17:58 ` Marc Zyngier [this message]
2023-02-09 17:58 ` [PATCH 04/18] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set Marc Zyngier
2023-02-09 17:58 ` [PATCH 05/18] KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x Marc Zyngier
2023-02-09 17:58 ` [PATCH 06/18] KVM: arm64: nv: Add EL2 system registers to vcpu context Marc Zyngier
2023-02-09 17:58 ` [PATCH 07/18] KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state Marc Zyngier
2023-02-09 17:58 ` [PATCH 08/18] KVM: arm64: nv: Handle HCR_EL2.NV system register traps Marc Zyngier
2023-02-24 17:39   ` Joey Gouly
2023-02-24 18:36     ` Oliver Upton
2023-02-24 19:03       ` Marc Zyngier
2023-02-09 17:58 ` [PATCH 09/18] KVM: arm64: nv: Support virtual EL2 exceptions Marc Zyngier
2023-02-09 17:58 ` [PATCH 10/18] KVM: arm64: nv: Inject HVC exceptions to the virtual EL2 Marc Zyngier
2023-02-09 17:58 ` [PATCH 11/18] KVM: arm64: nv: Handle trapped ERET from " Marc Zyngier
2023-02-09 17:58 ` [PATCH 12/18] KVM: arm64: nv: Handle PSCI call via smc from the guest Marc Zyngier
2023-02-11 10:07   ` Oliver Upton
2023-02-11 10:31     ` Marc Zyngier
2023-02-11 18:17       ` Oliver Upton
2023-02-09 17:58 ` [PATCH 13/18] KVM: arm64: nv: Add accessors for SPSR_EL1, ELR_EL1 and VBAR_EL1 from virtual EL2 Marc Zyngier
2023-02-09 17:58 ` [PATCH 14/18] KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor Marc Zyngier
2023-02-09 17:58 ` [PATCH 15/18] KVM: arm64: nv: Allow a sysreg to be hidden from userspace only Marc Zyngier
2023-02-09 17:58 ` [PATCH 16/18] KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2 Marc Zyngier
2023-02-09 17:58 ` [PATCH 17/18] KVM: arm64: nv: Filter out unsupported features from ID regs Marc Zyngier
2023-02-09 17:58 ` [PATCH 18/18] KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes Marc Zyngier
2023-02-13 22:26 ` [PATCH 00/18] KVM: arm64: Prefix patches for NV support Oliver Upton

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