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KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATE

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We currently have to maintain a mapping the thread_info structure
at EL2 in order to be able to check the TIF_FOREIGN_FPSTATE flag.

In order to eventually get rid of this, start with a vcpu flag that
shadows the thread flag on each entry into the hypervisor.

Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2021-10-21 14:10:35 +01:00
parent e66425fc9b
commit af9a0e21d8
4 changed files with 12 additions and 1 deletions
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2
arch/arm64/include/asm/kvm_host.h
View File

@ -441,6 +441,7 @@ struct kvm_vcpu_arch {
#define KVM_ARM64_DEBUG_STATE_SAVE_SPE (1 << 12) /* Save SPE context if active */
#define KVM_ARM64_DEBUG_STATE_SAVE_TRBE (1 << 13) /* Save TRBE context if active */
#define KVM_ARM64_FP_FOREIGN_FPSTATE (1 << 14)
#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \
KVM_GUESTDBG_USE_SW_BP | \
@ -736,6 +737,7 @@ long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm,
/* Guest/host FPSIMD coordination helpers */
int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);

1
arch/arm64/kvm/arm.c
View File

@ -849,6 +849,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
}
kvm_arm_setup_debug(vcpu);
kvm_arch_vcpu_ctxflush_fp(vcpu);
/**************************************************************
* Enter the guest

8
arch/arm64/kvm/fpsimd.c
View File

@ -79,6 +79,14 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;
}
void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)
{
if (test_thread_flag(TIF_FOREIGN_FPSTATE))
vcpu->arch.flags |= KVM_ARM64_FP_FOREIGN_FPSTATE;
else
vcpu->arch.flags &= ~KVM_ARM64_FP_FOREIGN_FPSTATE;
}
/*
* If the guest FPSIMD state was loaded, update the host's context
* tracking data mark the CPU FPSIMD regs as dirty and belonging to vcpu

2
arch/arm64/kvm/hyp/include/hyp/switch.h
View File

@ -49,7 +49,7 @@ static inline bool update_fp_enabled(struct kvm_vcpu *vcpu)
* trap the accesses.
*/
if (!system_supports_fpsimd() ||
vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
vcpu->arch.flags & KVM_ARM64_FP_FOREIGN_FPSTATE)
vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
KVM_ARM64_FP_HOST);