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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Andre Przywara <andre.przywara@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Jintack Lim <jintack@cs.columbia.edu>,
	Haibo Xu <haibo.xu@linaro.org>, James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	kernel-team@android.com, Jintack Lim <jintack.lim@linaro.org>
Subject: [PATCH v4 29/66] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization
Date: Mon, 10 May 2021 17:58:43 +0100	[thread overview]
Message-ID: <20210510165920.1913477-30-maz@kernel.org> (raw)
In-Reply-To: <20210510165920.1913477-1-maz@kernel.org>

From: Jintack Lim <jintack.lim@linaro.org>

We enable nested virtualization by setting the HCR NV and NV1 bit.

When the virtual E2H bit is set, we can support EL2 register accesses
via EL1 registers from the virtual EL2 by doing trap-and-emulate. A
better alternative, however, is to allow the virtual EL2 to access EL2
register states without trap. This can be easily achieved by not traping
EL1 registers since those registers already have EL2 register states.

Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/vhe/switch.c | 36 ++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index a238f52955c5..79789850639b 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -37,9 +37,39 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
 	u64 hcr = vcpu->arch.hcr_el2;
 	u64 val;
 
-	/* Trap VM sysreg accesses if an EL2 guest is not using VHE. */
-	if (vcpu_mode_el2(vcpu) && !vcpu_el2_e2h_is_set(vcpu))
-		hcr |= HCR_TVM | HCR_TRVM;
+	if (is_hyp_ctxt(vcpu)) {
+		hcr |= HCR_NV;
+
+		if (!vcpu_el2_e2h_is_set(vcpu)) {
+			/*
+			 * For a guest hypervisor on v8.0, trap and emulate
+			 * the EL1 virtual memory control register accesses.
+			 */
+			hcr |= HCR_TVM | HCR_TRVM | HCR_NV1;
+		} else {
+			/*
+			 * For a guest hypervisor on v8.1 (VHE), allow to
+			 * access the EL1 virtual memory control registers
+			 * natively. These accesses are to access EL2 register
+			 * states.
+			 * Note that we still need to respect the virtual
+			 * HCR_EL2 state.
+			 */
+			u64 vhcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);
+
+			/*
+			 * We already set TVM to handle set/way cache maint
+			 * ops traps, this somewhat collides with the nested
+			 * virt trapping for nVHE. So turn this off for now
+			 * here, in the hope that VHE guests won't ever do this.
+			 * TODO: find out whether it's worth to support both
+			 * cases at the same time.
+			 */
+			hcr &= ~HCR_TVM;
+
+			hcr |= vhcr_el2 & (HCR_TVM | HCR_TRVM);
+		}
+	}
 
 	___activate_traps(vcpu, hcr);
 
-- 
2.29.2


WARNING: multiple messages have this Message-ID
From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: kernel-team@android.com, Andre Przywara <andre.przywara@arm.com>,
	Jintack Lim <jintack.lim@linaro.org>
Subject: [PATCH v4 29/66] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization
Date: Mon, 10 May 2021 17:58:43 +0100	[thread overview]
Message-ID: <20210510165920.1913477-30-maz@kernel.org> (raw)
In-Reply-To: <20210510165920.1913477-1-maz@kernel.org>

From: Jintack Lim <jintack.lim@linaro.org>

We enable nested virtualization by setting the HCR NV and NV1 bit.

When the virtual E2H bit is set, we can support EL2 register accesses
via EL1 registers from the virtual EL2 by doing trap-and-emulate. A
better alternative, however, is to allow the virtual EL2 to access EL2
register states without trap. This can be easily achieved by not traping
EL1 registers since those registers already have EL2 register states.

Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/vhe/switch.c | 36 ++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index a238f52955c5..79789850639b 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -37,9 +37,39 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
 	u64 hcr = vcpu->arch.hcr_el2;
 	u64 val;
 
-	/* Trap VM sysreg accesses if an EL2 guest is not using VHE. */
-	if (vcpu_mode_el2(vcpu) && !vcpu_el2_e2h_is_set(vcpu))
-		hcr |= HCR_TVM | HCR_TRVM;
+	if (is_hyp_ctxt(vcpu)) {
+		hcr |= HCR_NV;
+
+		if (!vcpu_el2_e2h_is_set(vcpu)) {
+			/*
+			 * For a guest hypervisor on v8.0, trap and emulate
+			 * the EL1 virtual memory control register accesses.
+			 */
+			hcr |= HCR_TVM | HCR_TRVM | HCR_NV1;
+		} else {
+			/*
+			 * For a guest hypervisor on v8.1 (VHE), allow to
+			 * access the EL1 virtual memory control registers
+			 * natively. These accesses are to access EL2 register
+			 * states.
+			 * Note that we still need to respect the virtual
+			 * HCR_EL2 state.
+			 */
+			u64 vhcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);
+
+			/*
+			 * We already set TVM to handle set/way cache maint
+			 * ops traps, this somewhat collides with the nested
+			 * virt trapping for nVHE. So turn this off for now
+			 * here, in the hope that VHE guests won't ever do this.
+			 * TODO: find out whether it's worth to support both
+			 * cases at the same time.
+			 */
+			hcr &= ~HCR_TVM;
+
+			hcr |= vhcr_el2 & (HCR_TVM | HCR_TRVM);
+		}
+	}
 
 	___activate_traps(vcpu, hcr);
 
-- 
2.29.2

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID
From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Andre Przywara <andre.przywara@arm.com>,
	Christoffer Dall <christoffer.dall@arm.com>,
	Jintack Lim <jintack@cs.columbia.edu>,
	Haibo Xu <haibo.xu@linaro.org>, James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	kernel-team@android.com, Jintack Lim <jintack.lim@linaro.org>
Subject: [PATCH v4 29/66] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization
Date: Mon, 10 May 2021 17:58:43 +0100	[thread overview]
Message-ID: <20210510165920.1913477-30-maz@kernel.org> (raw)
In-Reply-To: <20210510165920.1913477-1-maz@kernel.org>

From: Jintack Lim <jintack.lim@linaro.org>

We enable nested virtualization by setting the HCR NV and NV1 bit.

When the virtual E2H bit is set, we can support EL2 register accesses
via EL1 registers from the virtual EL2 by doing trap-and-emulate. A
better alternative, however, is to allow the virtual EL2 to access EL2
register states without trap. This can be easily achieved by not traping
EL1 registers since those registers already have EL2 register states.

Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/hyp/vhe/switch.c | 36 ++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index a238f52955c5..79789850639b 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -37,9 +37,39 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
 	u64 hcr = vcpu->arch.hcr_el2;
 	u64 val;
 
-	/* Trap VM sysreg accesses if an EL2 guest is not using VHE. */
-	if (vcpu_mode_el2(vcpu) && !vcpu_el2_e2h_is_set(vcpu))
-		hcr |= HCR_TVM | HCR_TRVM;
+	if (is_hyp_ctxt(vcpu)) {
+		hcr |= HCR_NV;
+
+		if (!vcpu_el2_e2h_is_set(vcpu)) {
+			/*
+			 * For a guest hypervisor on v8.0, trap and emulate
+			 * the EL1 virtual memory control register accesses.
+			 */
+			hcr |= HCR_TVM | HCR_TRVM | HCR_NV1;
+		} else {
+			/*
+			 * For a guest hypervisor on v8.1 (VHE), allow to
+			 * access the EL1 virtual memory control registers
+			 * natively. These accesses are to access EL2 register
+			 * states.
+			 * Note that we still need to respect the virtual
+			 * HCR_EL2 state.
+			 */
+			u64 vhcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2);
+
+			/*
+			 * We already set TVM to handle set/way cache maint
+			 * ops traps, this somewhat collides with the nested
+			 * virt trapping for nVHE. So turn this off for now
+			 * here, in the hope that VHE guests won't ever do this.
+			 * TODO: find out whether it's worth to support both
+			 * cases at the same time.
+			 */
+			hcr &= ~HCR_TVM;
+
+			hcr |= vhcr_el2 & (HCR_TVM | HCR_TRVM);
+		}
+	}
 
 	___activate_traps(vcpu, hcr);
 
-- 
2.29.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2021-05-10 17:28 UTC|newest]

Thread overview: 226+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-10 16:58 [PATCH v4 00/66] KVM: arm64: ARMv8.3/8.4 Nested Virtualization support Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 01/66] arm64: Add ARM64_HAS_NESTED_VIRT cpufeature Marc Zyngier
2021-05-20 13:32   ` Zenghui Yu
2021-05-24 12:38     ` Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 02/66] KVM: arm64: nv: Introduce nested virtualization VCPU feature Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 03/66] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 04/66] KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 05/66] KVM: arm64: nv: Add EL2 system registers to vcpu context Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 06/66] KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 07/66] KVM: arm64: nv: Handle HCR_EL2.NV system register traps Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 08/66] KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 09/66] KVM: arm64: nv: Support virtual EL2 exceptions Marc Zyngier
2021-05-20 12:55   ` Zenghui Yu
2021-05-24 12:35     ` Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 10/66] KVM: arm64: nv: Inject HVC exceptions to the virtual EL2 Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 11/66] KVM: arm64: nv: Handle trapped ERET from " Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 12/66] KVM: arm64: nv: Add non-VHE-EL2->EL1 translation helpers Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 13/66] KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg() Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 14/66] KVM: arm64: nv: Handle SPSR_EL2 specially Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 15/66] KVM: arm64: nv: Handle HCR_EL2.E2H specially Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 16/66] KVM: arm64: nv: Save/Restore vEL2 sysregs Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 17/66] KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 18/66] KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2 Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 19/66] KVM: arm64: nv: Trap SPSR_EL1, ELR_EL1 and VBAR_EL1 from " Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 20/66] KVM: arm64: nv: Trap CPACR_EL1 access in " Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 21/66] KVM: arm64: nv: Handle PSCI call via smc from the guest Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 22/66] KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 23/66] KVM: arm64: nv: Respect virtual CPTR_EL2.{TFP, FPEN} settings Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 24/66] KVM: arm64: nv: Respect the virtual HCR_EL2.NV bit setting Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 25/66] KVM: arm64: nv: Respect virtual HCR_EL2.TVM and TRVM settings Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 26/66] KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 27/66] KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2 Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 28/66] KVM: arm64: nv: Forward debug traps to the nested guest Marc Zyngier
2021-05-10 16:58 ` Marc Zyngier [this message]
2021-05-10 16:58 ` [PATCH v4 30/66] KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 31/66] KVM: arm64: nv: Filter out unsupported features from ID regs Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 32/66] KVM: arm64: nv: Hide RAS from nested guests Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 33/66] KVM: arm64: nv: Support multiple nested Stage-2 mmu structures Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 34/66] KVM: arm64: nv: Implement nested Stage-2 page table walk logic Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 35/66] KVM: arm64: nv: Handle shadow stage 2 page faults Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 36/66] KVM: arm64: nv: Restrict S2 RD/WR permissions to match the guest's Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 37/66] KVM: arm64: nv: Unmap/flush shadow stage 2 page tables Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 38/66] KVM: arm64: nv: Introduce sys_reg_desc.forward_trap Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 39/66] KVM: arm64: nv: Set a handler for the system instruction traps Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 40/66] KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2 Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 41/66] KVM: arm64: nv: Trap and emulate TLBI " Marc Zyngier
2021-07-14 16:40   ` Chase Conklin
2021-05-10 16:58 ` [PATCH v4 42/66] KVM: arm64: nv: Fold guest's HCR_EL2 configuration into the host's Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 43/66] KVM: arm64: nv: arch_timer: Support hyp timer emulation Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 44/66] KVM: arm64: nv: Add handling of EL2-specific timer registers Marc Zyngier
2021-05-10 16:58 ` [PATCH v4 45/66] KVM: arm64: nv: Load timer before the GIC Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 46/66] KVM: arm64: nv: Nested GICv3 Support Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 47/66] KVM: arm64: nv: Don't load the GICv4 context on entering a nested guest Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 48/66] KVM: arm64: nv: vgic: Emulate the HW bit in software Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 49/66] KVM: arm64: nv: vgic: Allow userland to set VGIC maintenance IRQ Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 50/66] KVM: arm64: nv: Implement maintenance interrupt forwarding Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 51/66] KVM: arm64: nv: Add nested GICv3 tracepoints Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 52/66] KVM: arm64: nv: Allow userspace to request KVM_ARM_VCPU_NESTED_VIRT Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 53/66] KVM: arm64: nv: Add handling of ARMv8.4-TTL TLB invalidation Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 54/66] KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like information Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 55/66] KVM: arm64: Allow populating S2 SW bits Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 56/66] KVM: arm64: nv: Tag shadow S2 entries with nested level Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 57/66] KVM: arm64: nv: Add include containing the VNCR_EL2 offsets Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 58/66] KVM: arm64: Map VNCR-capable registers to a separate page Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 59/66] KVM: arm64: nv: Move nested vgic state into the sysreg file Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 60/66] KVM: arm64: Add ARMv8.4 Enhanced Nested Virt cpufeature Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 61/66] KVM: arm64: nv: Synchronize PSTATE early on exit Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 62/66] KVM: arm64: nv: Sync nested timer state with ARMv8.4 Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 63/66] KVM: arm64: nv: Allocate VNCR page when required Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 64/66] KVM: arm64: nv: Enable ARMv8.4-NV support Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 65/66] KVM: arm64: nv: Fast-track 'InHost' exception returns Marc Zyngier
2021-05-10 16:59 ` [PATCH v4 66/66] KVM: arm64: nv: Fast-track EL1 TLBIs for VHE guests Marc Zyngier
2021-06-03  7:07 ` [PATCH v4 00/66] KVM: arm64: ARMv8.3/8.4 Nested Virtualization support Jamie Iles
2021-06-03  8:39   ` Marc Zyngier
2021-06-03 11:08     ` Marc Zyngier
2021-06-07  9:59     ` Jamie Iles

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