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From: Shaoqin Huang <shahuang@redhat.com>
To: Oliver Upton <oliver.upton@linux.dev>,
	Marc Zyngier <maz@kernel.org>,
	kvmarm@lists.linux.dev, Mark Brown <broonie@kernel.org>
Cc: Eric Auger <eauger@redhat.com>, Sebastian Ott <sebott@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Shaoqin Huang <shahuang@redhat.com>,
	James Morse <james.morse@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5 2/4] KVM: arm64: Use kvm_has_feat() to check if FEAT_SSBS is advertised to the guest
Date: Tue, 23 Jul 2024 03:20:01 -0400	[thread overview]
Message-ID: <20240723072004.1470688-3-shahuang@redhat.com> (raw)
In-Reply-To: <20240723072004.1470688-1-shahuang@redhat.com>

Currently KVM use cpus_have_final_cap() to check if FEAT_SSBS is
advertised to the guest. But if FEAT_SSBS is writable and isn't
advertised to the guest, this is wrong.

Update it to use kvm_has_feat() to check if FEAT_SSBS is advertised
to the guest, thus the KVM can do the right thing if FEAT_SSBS isn't
advertised to the guest.

Signed-off-by: Shaoqin Huang <shahuang@redhat.com>
---
 arch/arm64/kvm/hypercalls.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5763d979d8ca..ee6573befb81 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -317,7 +317,7 @@ int kvm_smccc_call_handler(struct kvm_vcpu *vcpu)
 				 * to the guest, and hide SSBS so that the
 				 * guest stays protected.
 				 */
-				if (cpus_have_final_cap(ARM64_SSBS))
+				if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, SSBS, IMP))
 					break;
 				fallthrough;
 			case SPECTRE_UNAFFECTED:
@@ -428,7 +428,7 @@ int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
  * Convert the workaround level into an easy-to-compare number, where higher
  * values mean better protection.
  */
-static int get_kernel_wa_level(u64 regid)
+static int get_kernel_wa_level(struct kvm_vcpu *vcpu, u64 regid)
 {
 	switch (regid) {
 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
@@ -449,7 +449,7 @@ static int get_kernel_wa_level(u64 regid)
 			 * don't have any FW mitigation if SSBS is there at
 			 * all times.
 			 */
-			if (cpus_have_final_cap(ARM64_SSBS))
+			if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, SSBS, IMP))
 				return KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL;
 			fallthrough;
 		case SPECTRE_UNAFFECTED:
@@ -486,7 +486,7 @@ int kvm_arm_get_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
 	case KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_3:
-		val = get_kernel_wa_level(reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
+		val = get_kernel_wa_level(vcpu, reg->id) & KVM_REG_FEATURE_LEVEL_MASK;
 		break;
 	case KVM_REG_ARM_STD_BMAP:
 		val = READ_ONCE(smccc_feat->std_bmap);
@@ -588,7 +588,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 		if (val & ~KVM_REG_FEATURE_LEVEL_MASK)
 			return -EINVAL;
 
-		if (get_kernel_wa_level(reg->id) < val)
+		if (get_kernel_wa_level(vcpu, reg->id) < val)
 			return -EINVAL;
 
 		return 0;
@@ -624,7 +624,7 @@ int kvm_arm_set_fw_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 		 * We can deal with NOT_AVAIL on NOT_REQUIRED, but not the
 		 * other way around.
 		 */
-		if (get_kernel_wa_level(reg->id) < wa_level)
+		if (get_kernel_wa_level(vcpu, reg->id) < wa_level)
 			return -EINVAL;
 
 		return 0;
-- 
2.40.1



  parent reply	other threads:[~2024-07-23  7:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-23  7:19 [PATCH v5 0/4] Allow userspace to change ID_AA64PFR1_EL1 Shaoqin Huang
2024-07-23  7:20 ` [PATCH v5 1/4] KVM: arm64: Disable fields that KVM doesn't know how to handle in ID_AA64PFR1_EL1 Shaoqin Huang
2024-07-23  7:20 ` Shaoqin Huang [this message]
2024-07-23  7:20 ` [PATCH v5 3/4] KVM: arm64: Allow userspace to change ID_AA64PFR1_EL1 Shaoqin Huang
2024-07-23  7:20 ` [PATCH v5 4/4] KVM: selftests: aarch64: Add writable test for ID_AA64PFR1_EL1 Shaoqin Huang
2024-08-21  2:45 ` [PATCH v5 0/4] Allow userspace to change ID_AA64PFR1_EL1 Shaoqin Huang
2024-08-25 16:46 ` Marc Zyngier
2024-08-25 17:09   ` Russell King (Oracle)
2024-08-25 19:45     ` Marc Zyngier
2024-08-25 17:01 ` Marc Zyngier

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