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From: Andrew Scull <ascull@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, kernel-team@android.com
Subject: [PATCH 14/37] KVM: arm64: nVHE: Use __kvm_vcpu_run for the host vcpu
Date: Wed, 15 Jul 2020 19:44:15 +0100
Message-ID: <20200715184438.1390996-15-ascull@google.com> (raw)
In-Reply-To: <20200715184438.1390996-1-ascull@google.com>

Keeping the assumption that transitions will only be from the host to a
guest and vice-versa, make __kvm_vcpu_run switch to the requested vcpu
and run it.

The context is only switched when it is not currently active allowing
the host to be run repeatedly when servicing HVCs.

Signed-off-by: Andrew Scull <ascull@google.com>
---
 arch/arm64/kvm/hyp/nvhe/hyp-main.c | 22 ++-----
 arch/arm64/kvm/hyp/nvhe/switch.c   | 95 ++++++++++++++++++++++--------
 2 files changed, 74 insertions(+), 43 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 2d621bf5ac3e..213977634601 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -115,10 +115,8 @@ void __noreturn kvm_hyp_main(void)
 {
 	/* Set tpidr_el2 for use by HYP */
 	struct kvm_vcpu *host_vcpu;
-	struct kvm_cpu_context *hyp_ctxt;
 
 	host_vcpu = __hyp_this_cpu_ptr(kvm_host_vcpu);
-	hyp_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
 
 	kvm_init_host_cpu_context(&host_vcpu->arch.ctxt);
 
@@ -131,24 +129,14 @@ void __noreturn kvm_hyp_main(void)
 	 */
 	smccc_set_retval(host_vcpu, SMCCC_RET_SUCCESS, 0, 0, 0);
 
+	/* The host is already loaded so note it as the running vcpu. */
+	*__hyp_this_cpu_ptr(kvm_hyp_running_vcpu) = host_vcpu;
+
 	while (true) {
 		u64 exit_code;
 
-		/*
-		 * Set the running cpu for the vectors to pass to __guest_exit
-		 * so it can get the cpu context.
-		 */
-		*__hyp_this_cpu_ptr(kvm_hyp_running_vcpu) = host_vcpu;
-
-		/*
-		 * Enter the host now that we feel like we're in charge.
-		 *
-		 * This should merge with __kvm_vcpu_run as host becomes more
-		 * vcpu-like.
-		 */
-		do {
-			exit_code = __guest_enter(host_vcpu, hyp_ctxt);
-		} while (fixup_guest_exit(host_vcpu, &exit_code));
+		/* Enter the host now that we feel like we're in charge. */
+		exit_code = __kvm_vcpu_run(host_vcpu);
 
 		switch (ARM_EXCEPTION_CODE(exit_code)) {
 		case ARM_EXCEPTION_TRAP:
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 81cdf33f92bc..36140686e1d8 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -119,7 +119,7 @@ static void __hyp_vgic_restore_state(struct kvm_vcpu *vcpu)
 /**
  * Disable host events, enable guest events
  */
-static bool __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
+static void __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
 {
 	struct kvm_host_data *host;
 	struct kvm_pmu_events *pmu;
@@ -132,8 +132,6 @@ static bool __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt)
 
 	if (pmu->events_guest)
 		write_sysreg(pmu->events_guest, pmcntenset_el0);
-
-	return (pmu->events_host || pmu->events_guest);
 }
 
 /**
@@ -154,13 +152,10 @@ static void __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt)
 		write_sysreg(pmu->events_host, pmcntenset_el0);
 }
 
-/* Switch to the guest for legacy non-VHE systems */
-int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
+static void __kvm_vcpu_switch_to_guest(struct kvm_cpu_context *host_ctxt,
+				       struct kvm_vcpu *vcpu)
 {
-	struct kvm_cpu_context *host_ctxt;
-	struct kvm_cpu_context *guest_ctxt;
-	bool pmu_switch_needed;
-	u64 exit_code;
+	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
 
 	/*
 	 * Having IRQs masked via PMR when entering the guest means the GIC
@@ -173,11 +168,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 		pmr_sync();
 	}
 
-	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
-	*__hyp_this_cpu_ptr(kvm_hyp_running_vcpu) = vcpu;
-	guest_ctxt = &vcpu->arch.ctxt;
-
-	pmu_switch_needed = __pmu_switch_to_guest(host_ctxt);
+	__pmu_switch_to_guest(host_ctxt);
 
 	__sysreg_save_state_nvhe(host_ctxt);
 
@@ -199,17 +190,13 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 	__timer_enable_traps(vcpu);
 
 	__debug_switch_to_guest(vcpu);
+}
 
-	__set_vcpu_arch_workaround_state(vcpu);
-
-	do {
-		/* Jump in the fire! */
-		exit_code = __guest_enter(vcpu, host_ctxt);
-
-		/* And we're baaack! */
-	} while (fixup_guest_exit(vcpu, &exit_code));
-
-	__set_hyp_arch_workaround_state(vcpu);
+static void __kvm_vcpu_switch_to_host(struct kvm_cpu_context *host_ctxt,
+				      struct kvm_vcpu *host_vcpu,
+				      struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *guest_ctxt = &vcpu->arch.ctxt;
 
 	__sysreg_save_state_nvhe(guest_ctxt);
 	__sysreg32_save_state(vcpu);
@@ -230,12 +217,68 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 	 */
 	__debug_switch_to_host(vcpu);
 
-	if (pmu_switch_needed)
-		__pmu_switch_to_host(host_ctxt);
+	__pmu_switch_to_host(host_ctxt);
 
 	/* Returning to host will clear PSR.I, remask PMR if needed */
 	if (system_uses_irq_prio_masking())
 		gic_write_pmr(GIC_PRIO_IRQOFF);
+}
+
+static void __vcpu_switch_to(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *host_ctxt;
+	struct kvm_vcpu *running_vcpu;
+
+	/*
+	 * Restoration is not yet pure so it still makes use of the previously
+	 * running vcpu.
+	 */
+	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+	running_vcpu = __hyp_this_cpu_read(kvm_hyp_running_vcpu);
+
+	if (vcpu->arch.ctxt.is_host)
+		__kvm_vcpu_switch_to_host(host_ctxt, vcpu, running_vcpu);
+	else
+		__kvm_vcpu_switch_to_guest(host_ctxt, vcpu);
+
+	*__hyp_this_cpu_ptr(kvm_hyp_running_vcpu) = vcpu;
+}
+
+/* Switch to the guest for legacy non-VHE systems */
+int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpu_context *host_ctxt;
+	struct kvm_vcpu *running_vcpu;
+	u64 exit_code;
+
+	host_ctxt = &__hyp_this_cpu_ptr(kvm_host_data)->host_ctxt;
+	running_vcpu = __hyp_this_cpu_read(kvm_hyp_running_vcpu);
+
+	if (running_vcpu != vcpu) {
+		if (!running_vcpu->arch.ctxt.is_host &&
+		    !vcpu->arch.ctxt.is_host) {
+			/*
+			 * There are still assumptions that the switch will
+			 * always be between a guest and the host so double
+			 * check that is the case. If it isn't, pretending
+			 * there was an interrupt is a harmless way to bail.
+			 */
+			return ARM_EXCEPTION_IRQ;
+		}
+
+		__vcpu_switch_to(vcpu);
+	}
+
+	__set_vcpu_arch_workaround_state(vcpu);
+
+	do {
+		/* Jump in the fire! */
+		exit_code = __guest_enter(vcpu, host_ctxt);
+
+		/* And we're baaack! */
+	} while (fixup_guest_exit(vcpu, &exit_code));
+
+	__set_hyp_arch_workaround_state(vcpu);
 
 	return exit_code;
 }
-- 
2.27.0.389.gc38d7665816-goog

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  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-15 18:44 [PATCH 00/37] Transform the host into a vCPU Andrew Scull
2020-07-15 18:44 ` [PATCH 01/37] smccc: Make constants available to assembly Andrew Scull
2020-07-15 18:44 ` [PATCH 02/37] KVM: arm64: Move clearing of vcpu debug dirty bit Andrew Scull
2020-07-15 18:44 ` [PATCH 03/37] KVM: arm64: Track running vCPU outside of the CPU context Andrew Scull
2020-07-15 18:44 ` [PATCH 04/37] KVM: arm64: nVHE: Pass pointers consistently to hyp-init Andrew Scull
2020-07-15 18:44 ` [PATCH 05/37] KVM: arm64: nVHE: Break out of the hyp-init idmap Andrew Scull
2020-07-15 18:44 ` [PATCH 06/37] KVM: arm64: Only check pending interrupts if it would trap Andrew Scull
2020-07-17 16:21   ` Marc Zyngier
2020-07-15 18:44 ` [PATCH 07/37] KVM: arm64: Separate SError detection from VAXorcism Andrew Scull
2020-07-18  9:00   ` Marc Zyngier
2020-07-20 14:13     ` Andrew Scull
2020-07-20 14:56       ` Marc Zyngier
2020-07-23  0:59         ` FW: " Renters Cancellation Requests
2020-07-20 15:40   ` Andrew Scull
2020-07-20 15:57     ` Marc Zyngier
2020-07-15 18:44 ` [PATCH 08/37] KVM: arm64: nVHE: Introduce a hyp run loop for the host Andrew Scull
2020-07-15 18:44 ` [PATCH 09/37] smccc: Cast arguments to unsigned long Andrew Scull
2020-07-15 18:44 ` [PATCH 10/37] KVM: arm64: nVHE: Migrate hyp interface to SMCCC Andrew Scull
2020-07-15 18:44 ` [PATCH 11/37] KVM: arm64: nVHE: Migrate hyp-init " Andrew Scull
2020-07-15 18:44 ` [PATCH 12/37] KVM: arm64: nVHE: Fix pointers during SMCCC convertion Andrew Scull
2020-07-15 18:44 ` [PATCH 13/37] KVM: arm64: Rename workaround 2 helpers Andrew Scull
2020-07-15 18:44 ` Andrew Scull [this message]
2020-07-15 18:44 ` [PATCH 15/37] KVM: arm64: Share some context save and restore macros Andrew Scull
2020-07-15 18:44 ` [PATCH 16/37] KVM: arm64: nVHE: Handle stub HVCs in the host loop Andrew Scull
2020-07-15 18:44 ` [PATCH 17/37] KVM: arm64: nVHE: Store host sysregs in host vcpu Andrew Scull
2020-07-15 18:44 ` [PATCH 18/37] KVM: arm64: nVHE: Access pmu_events directly in kvm_host_data Andrew Scull
2020-07-15 18:44 ` [PATCH 19/37] KVM: arm64: nVHE: Drop host_ctxt argument for context switching Andrew Scull
2020-07-15 18:44 ` [PATCH 20/37] KVM: arm64: nVHE: Use host vcpu context for host debug state Andrew Scull
2020-07-15 18:44 ` [PATCH 21/37] KVM: arm64: Move host debug state from vcpu to percpu Andrew Scull
2020-07-15 18:44 ` [PATCH 22/37] KVM: arm64: nVHE: Store host's mdcr_el2 and hcr_el2 in its vcpu Andrew Scull
2020-07-15 18:44 ` [PATCH 23/37] KVM: arm64: Skip __hyp_panic and go direct to hyp_panic Andrew Scull
2020-07-15 18:44 ` [PATCH 24/37] KVM: arm64: Break apart kvm_host_data Andrew Scull
2020-07-15 18:44 ` [PATCH 25/37] KVM: arm64: nVHE: Unify sysreg state saving paths Andrew Scull
2020-07-15 18:44 ` [PATCH 26/37] KVM: arm64: nVHE: Unify 32-bit sysreg " Andrew Scull
2020-07-15 18:44 ` [PATCH 27/37] KVM: arm64: nVHE: Unify vgic save and restore Andrew Scull
2020-07-15 18:44 ` [PATCH 28/37] KVM: arm64: nVHE: Unify fpexc32 saving paths Andrew Scull
2020-07-15 18:44 ` [PATCH 29/37] KVM: arm64: nVHE: Separate the save and restore of debug state Andrew Scull
2020-07-15 18:44 ` [PATCH 30/37] KVM: arm64: nVHE: Remove MMU assumption in speculative AT workaround Andrew Scull
2020-07-15 18:44 ` [PATCH 31/37] KVM: arm64: Move speculative AT ISBs into context Andrew Scull
2020-07-15 18:44 ` [PATCH 32/37] KVM: arm64: nVHE: Unify sysreg state restoration paths Andrew Scull
2020-07-15 18:44 ` [PATCH 33/37] KVM: arm64: Remove __activate_vm wrapper Andrew Scull
2020-07-15 18:44 ` [PATCH 34/37] KVM: arm64: nVHE: Unify timer restore paths Andrew Scull
2020-07-15 18:44 ` [PATCH 35/37] KVM: arm64: nVHE: Unify PMU event restoration paths Andrew Scull
2020-07-15 18:44 ` [PATCH 36/37] KVM: arm64: nVHE: Unify GIC PMR " Andrew Scull
2020-07-15 18:44 ` [PATCH 37/37] KVM: arm64: Separate save and restore of vcpu trap state Andrew Scull

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