diff mbox series

[RFC,kvmtool,07/31] arm64: Add option to disable SVE

Message ID 20230127113932.166089-8-suzuki.poulose@arm.com
State New
Headers
Series arm64: Support for Arm Confidential Compute Architecture |

Commit Message

Suzuki K Poulose Jan. 27, 2023, 11:39 a.m. UTC 
  kvmtool enables SVE whenever it is supported by the KVM.
However, Realm VMs may want controlled features, which gets
measured during the creation. Thus, provide an option to disable
the SVE, to preserve the current behavior of SVE on by default.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 arm/aarch64/include/kvm/kvm-config-arch.h | 4 +++-
 arm/aarch64/kvm-cpu.c                     | 8 +++++---
 arm/include/arm-common/kvm-config-arch.h  | 1 +
 3 files changed, 9 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h
index eae8080d..b055fef4 100644
--- a/arm/aarch64/include/kvm/kvm-config-arch.h
+++ b/arm/aarch64/include/kvm/kvm-config-arch.h
@@ -19,7 +19,9 @@  int vcpu_affinity_parser(const struct option *opt, const char *arg, int unset);
 			"Specify random seed for Kernel Address Space "	\
 			"Layout Randomization (KASLR)"),		\
 	OPT_BOOLEAN('\0', "no-pvtime", &(cfg)->no_pvtime, "Disable"	\
-			" stolen time"),
+			" stolen time"),				\
+	OPT_BOOLEAN('\0', "disable-sve", &(cfg)->disable_sve,		\
+			"Disable SVE"),
 #include "arm-common/kvm-config-arch.h"
 
 #endif /* KVM__KVM_CONFIG_ARCH_H */
diff --git a/arm/aarch64/kvm-cpu.c b/arm/aarch64/kvm-cpu.c
index da809806..e7649239 100644
--- a/arm/aarch64/kvm-cpu.c
+++ b/arm/aarch64/kvm-cpu.c
@@ -149,8 +149,9 @@  void kvm_cpu__select_features(struct kvm *kvm, struct kvm_vcpu_init *init)
 		init->features[0] |= 1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC;
 	}
 
-	/* Enable SVE if available */
-	if (kvm__supports_vm_extension(kvm, KVM_CAP_ARM_SVE))
+	/* If SVE is not disabled explicitly, enable if available */
+	if (!kvm->cfg.arch.disable_sve &&
+	    kvm__supports_vm_extension(kvm, KVM_CAP_ARM_SVE))
 		init->features[0] |= 1UL << KVM_ARM_VCPU_SVE;
 }
 
@@ -158,7 +159,8 @@  int kvm_cpu__configure_features(struct kvm_cpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
 
-	if (kvm__supports_vm_extension(kvm, KVM_CAP_ARM_SVE)) {
+	if (!kvm->cfg.arch.disable_sve &&
+	    kvm__supports_vm_extension(kvm, KVM_CAP_ARM_SVE)) {
 		int feature = KVM_ARM_VCPU_SVE;
 
 		if (ioctl(vcpu->vcpu_fd, KVM_ARM_VCPU_FINALIZE, &feature)) {
diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h
index 9949bfe4..6599305b 100644
--- a/arm/include/arm-common/kvm-config-arch.h
+++ b/arm/include/arm-common/kvm-config-arch.h
@@ -15,6 +15,7 @@  struct kvm_config_arch {
 	enum irqchip_type irqchip;
 	u64		fw_addr;
 	bool no_pvtime;
+	bool		disable_sve;
 };
 
 int irqchip_parser(const struct option *opt, const char *arg, int unset);