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From: Oliver Upton <oliver.upton@linux.dev>
To: kvmarm@lists.linux.dev
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Sean Christopherson <seanjc@google.com>,
	Salil Mehta <salil.mehta@huawei.com>,
	Oliver Upton <oliver.upton@linux.dev>
Subject: [PATCH 05/11] KVM: arm64: Start handling SMCs from EL1
Date: Mon, 20 Mar 2023 22:09:56 +0000	[thread overview]
Message-ID: <20230320221002.4191007-6-oliver.upton@linux.dev> (raw)
In-Reply-To: <20230320221002.4191007-1-oliver.upton@linux.dev>

Whelp, the architecture gods have spoken and confirmed that the function
ID space is common between SMCs and HVCs. Not only that, the expectation
is that hypervisors handle calls to both SMC and HVC conduits. KVM
recently picked up support for SMCCCs in commit bd36b1a9eb5a ("KVM:
arm64: nv: Handle SMCs taken from virtual EL2") but scoped it only to a
nested hypervisor.

Let's just open the floodgates and let EL1 access our SMCCC
implementation with the SMC instruction as well.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/handle_exit.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index 5e4f9737cbd5..68f95dcd41a1 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -72,13 +72,15 @@ static int handle_smc(struct kvm_vcpu *vcpu)
 	 *
 	 * We need to advance the PC after the trap, as it would
 	 * otherwise return to the same address...
-	 *
-	 * Only handle SMCs from the virtual EL2 with an immediate of zero and
-	 * skip it otherwise.
 	 */
-	if (!vcpu_is_el2(vcpu) || kvm_vcpu_hvc_get_imm(vcpu)) {
+	kvm_incr_pc(vcpu);
+
+	/*
+	 * SMCs with a nonzero immediate are reserved according to DEN0028E 2.9
+	 * "SMC and HVC immediate value".
+	 */
+	if (kvm_vcpu_hvc_get_imm(vcpu)) {
 		vcpu_set_reg(vcpu, 0, ~0UL);
-		kvm_incr_pc(vcpu);
 		return 1;
 	}
 
@@ -93,8 +95,6 @@ static int handle_smc(struct kvm_vcpu *vcpu)
 	if (ret < 0)
 		vcpu_set_reg(vcpu, 0, ~0UL);
 
-	kvm_incr_pc(vcpu);
-
 	return ret;
 }
 
-- 
2.40.0.rc1.284.g88254d51c5-goog


  parent reply	other threads:[~2023-03-20 22:10 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-20 22:09 [PATCH 00/11] KVM: arm64: Userspace SMCCC call filtering Oliver Upton
2023-03-20 22:09 ` [PATCH 01/11] KVM: x86: Redefine 'longmode' as a flag for KVM_EXIT_HYPERCALL Oliver Upton
2023-03-21 15:53   ` Sean Christopherson
2023-03-21 17:36     ` Oliver Upton
2023-03-20 22:09 ` [PATCH 02/11] KVM: arm64: Add a helper to check if a VM has ran once Oliver Upton
2023-03-21  9:42   ` Suzuki K Poulose
2023-03-21 16:29     ` Oliver Upton
2023-03-20 22:09 ` [PATCH 03/11] KVM: arm64: Add vm fd device attribute accessors Oliver Upton
2023-03-21  9:53   ` Suzuki K Poulose
2023-03-21 16:49     ` Oliver Upton
2023-03-28  8:39       ` Suzuki K Poulose
2023-03-28  8:40   ` Suzuki K Poulose
2023-03-20 22:09 ` [PATCH 04/11] KVM: arm64: Rename SMC/HVC call handler to reflect reality Oliver Upton
2023-03-21  9:52   ` Suzuki K Poulose
2023-03-28  8:40   ` Suzuki K Poulose
2023-03-20 22:09 ` Oliver Upton [this message]
2023-03-28  8:52   ` [PATCH 05/11] KVM: arm64: Start handling SMCs from EL1 Suzuki K Poulose
2023-03-28 14:15     ` Marc Zyngier
2023-03-20 22:09 ` [PATCH 06/11] KVM: arm64: Refactor hvc filtering to support different actions Oliver Upton
2023-03-28  9:19   ` Suzuki K Poulose
2023-03-20 22:09 ` [PATCH 07/11] KVM: arm64: Use a maple tree to represent the SMCCC filter Oliver Upton
2023-03-20 22:09 ` [PATCH 08/11] KVM: arm64: Add support for KVM_EXIT_HYPERCALL Oliver Upton
2023-03-20 22:10 ` [PATCH 09/11] KVM: arm64: Indroduce support for userspace SMCCC filtering Oliver Upton
2023-03-20 22:10 ` [PATCH 10/11] KVM: selftests: Add a helper for SMCCC calls with SMC instruction Oliver Upton
2023-03-20 22:10 ` [PATCH 11/11] KVM: selftests: Add test for SMCCC filter Oliver Upton

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