If the system doesn't support FPSIMD features then the flags must never
be set. These are the same feature checks performed by hyp when handling
an FPSIMD trap.
Signed-off-by: Andrew Scull <ascull@xxxxxxxxxx>
---
arch/arm64/kvm/fpsimd.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
index 3e081d556e81..c6b3197f6754 100644
--- a/arch/arm64/kvm/fpsimd.c
+++ b/arch/arm64/kvm/fpsimd.c
@@ -52,7 +52,7 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
* Prepare vcpu for saving the host's FPSIMD state and loading the guest's.
* The actual loading is done by the FPSIMD access trap taken to hyp.
*
- * Here, we just set the correct metadata to indicate that the FPSIMD
+ * Here, we just set the correct metadata to indicate whether the FPSIMD
* state in the cpu regs (if any) belongs to current on the host.
*
* TIF_SVE is backed up here, since it may get clobbered with guest state.
@@ -63,15 +63,29 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
BUG_ON(!current->mm);
vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
+ KVM_ARM64_FP_HOST |
KVM_ARM64_HOST_SVE_IN_USE |
KVM_ARM64_HOST_SVE_ENABLED);
+
+ if (!system_supports_fpsimd())
+ return;
+
+ /*
+ * Having just come from the user task, if any FP state is loaded it
+ * will be that of the task. Make a note of this but, just before
+ * entering the vcpu, it will be double checked that the loaded FP
+ * state isn't transient because things could change between now and
+ * then.
+ */
vcpu->arch.flags |= KVM_ARM64_FP_HOST;
- if (test_thread_flag(TIF_SVE))
- vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;
+ if (system_supports_sve()) {
+ if (test_thread_flag(TIF_SVE))
+ vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;
- if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)
- vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;
+ if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)
+ vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;
+ }
}
/*
--
2.27.0.383.g050319c2ae-goog
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