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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: James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Andrew Scull <ascull@google.com>, Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Quentin Perret <qperret@google.com>,
	David Brazdil <dbrazdil@google.com>,
	kernel-team@android.com
Subject: [PATCH v2 04/11] KVM: arm64: Move PC rollback on SError to HYP
Date: Mon,  2 Nov 2020 16:40:38 +0000	[thread overview]
Message-ID: <20201102164045.264512-5-maz@kernel.org> (raw)
In-Reply-To: <20201102164045.264512-1-maz@kernel.org>

Instead of handling the "PC rollback on SError during HVC" at EL1 (which
requires disclosing PC to a potentially untrusted kernel), let's move
this fixup to ... fixup_guest_exit(), which is where we do all fixups.

Isn't that neat?

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/handle_exit.c            | 17 -----------------
 arch/arm64/kvm/hyp/include/hyp/switch.h | 15 +++++++++++++++
 2 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index d4e00a864ee6..f79137ee4274 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -241,23 +241,6 @@ int handle_exit(struct kvm_vcpu *vcpu, int exception_index)
 {
 	struct kvm_run *run = vcpu->run;
 
-	if (ARM_SERROR_PENDING(exception_index)) {
-		u8 esr_ec = ESR_ELx_EC(kvm_vcpu_get_esr(vcpu));
-
-		/*
-		 * HVC already have an adjusted PC, which we need to
-		 * correct in order to return to after having injected
-		 * the SError.
-		 *
-		 * SMC, on the other hand, is *trapped*, meaning its
-		 * preferred return address is the SMC itself.
-		 */
-		if (esr_ec == ESR_ELx_EC_HVC32 || esr_ec == ESR_ELx_EC_HVC64)
-			*vcpu_pc(vcpu) -= 4;
-
-		return 1;
-	}
-
 	exception_index = ARM_EXCEPTION_CODE(exception_index);
 
 	switch (exception_index) {
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 8b2328f62a07..84473574c2e7 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -411,6 +411,21 @@ static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
 	if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ)
 		vcpu->arch.fault.esr_el2 = read_sysreg_el2(SYS_ESR);
 
+	if (ARM_SERROR_PENDING(*exit_code)) {
+		u8 esr_ec = kvm_vcpu_trap_get_class(vcpu);
+
+		/*
+		 * HVC already have an adjusted PC, which we need to
+		 * correct in order to return to after having injected
+		 * the SError.
+		 *
+		 * SMC, on the other hand, is *trapped*, meaning its
+		 * preferred return address is the SMC itself.
+		 */
+		if (esr_ec == ESR_ELx_EC_HVC32 || esr_ec == ESR_ELx_EC_HVC64)
+			write_sysreg_el2(read_sysreg_el2(SYS_ELR) - 4, SYS_ELR);
+	}
+
 	/*
 	 * We're using the raw exception code in order to only process
 	 * the trap if no SError is pending. We will come back to the
-- 
2.28.0


  parent reply	other threads:[~2020-11-02 16:41 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-02 16:40 [PATCH v2 00/11] KVM: arm64: Move PC/ELR/SPSR/PSTATE updatess to EL2 Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 01/11] KVM: arm64: Don't adjust PC on SError during SMC trap Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 02/11] KVM: arm64: Move kvm_vcpu_trap_il_is32bit into kvm_skip_instr32() Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 03/11] KVM: arm64: Make kvm_skip_instr() and co private to HYP Marc Zyngier
2021-05-05 14:23   ` Zenghui Yu
2021-05-05 16:46     ` Marc Zyngier
2021-05-06  6:33       ` Marc Zyngier
2021-05-06 11:43         ` Zenghui Yu
2021-05-06 14:29           ` Marc Zyngier
2021-05-09 13:07             ` Zenghui Yu
2021-05-10  7:59               ` Marc Zyngier
2021-05-06 17:17     ` Marc Zyngier
2020-11-02 16:40 ` Marc Zyngier [this message]
2020-11-02 16:40 ` [PATCH v2 05/11] KVM: arm64: Move VHE direct sysreg accessors into kvm_host.h Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 06/11] KVM: arm64: Add basic hooks for injecting exceptions from EL2 Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 07/11] KVM: arm64: Inject AArch64 exceptions from HYP Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 08/11] KVM: arm64: Inject AArch32 " Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 09/11] KVM: arm64: Remove SPSR manipulation primitives Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 10/11] KVM: arm64: Consolidate exception injection Marc Zyngier
2020-11-02 16:40 ` [PATCH v2 11/11] KVM: arm64: Get rid of the AArch32 register mapping code Marc Zyngier

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