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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
Subject: [PATCH v4 15/66] KVM: arm64: nv: Handle HCR_EL2.E2H specially
Date: Mon, 10 May 2021 17:58:29 +0100	[thread overview]
Message-ID: <20210510165920.1913477-16-maz@kernel.org> (raw)
In-Reply-To: <20210510165920.1913477-1-maz@kernel.org>

HCR_EL2.E2H is nasty, as a flip of this bit completely changes the way
we deal with a lot of the state. So when the guest flips this bit
(sysregs are live), do the put/load dance so that we have a consistent
state.

Yes, this is slow. Don't do it.

Suggested-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 2c1ab8cd58b4..0d29d9d59c3f 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -187,9 +187,24 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
 		goto memory_write;
 
 	if (unlikely(get_el2_mapping(reg, &el1r, &xlate))) {
+		bool need_put_load;
+
 		if (!is_hyp_ctxt(vcpu))
 			goto memory_write;
 
+		/*
+		 * HCR_EL2.E2H is nasty: it changes the way we interpret a
+		 * lot of the EL2 state, so treat is as a full state
+		 * transition.
+		 */
+		need_put_load = ((reg == HCR_EL2) &&
+				 vcpu_el2_e2h_is_set(vcpu) != !!(val & HCR_E2H));
+
+		if (need_put_load) {
+			preempt_disable();
+			kvm_arch_vcpu_put(vcpu);
+		}
+
 		/*
 		 * Always store a copy of the write to memory to avoid having
 		 * to reverse-translate virtual EL2 system registers for a
@@ -197,6 +212,11 @@ void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
 		 */
 		__vcpu_sys_reg(vcpu, reg) = val;
 
+		if (need_put_load) {
+			kvm_arch_vcpu_load(vcpu, smp_processor_id());
+			preempt_enable();
+		}
+
 		switch (reg) {
 		case ELR_EL2:
 			write_sysreg_el1(val, SYS_ELR);
-- 
2.29.2


  parent reply	other threads:[~2021-05-10 17:29 UTC|newest]

Thread overview: 75+ 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
2021-05-10 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
2021-05-10 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 ` Marc Zyngier [this message]
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 ` [PATCH v4 29/66] KVM: arm64: nv: Configure HCR_EL2 for nested virtualization Marc Zyngier
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
2021-11-29 18:12     ` Marc Zyngier
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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