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| author | Marc Zyngier <maz@kernel.org> | 2022-02-08 15:44:46 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2022-02-08 15:44:46 +0100 |
| commit | 64330073b8efe9ea6ccbd451144ceb7178b54d04 (patch) | |
| tree | 861fbd160f7b2c10567e074fc5685efe7b36fbc3 /arch/arm64/kvm | |
| parent | Merge branch kvm-arm64/mmu-rwlock into kvmarm-master/next (diff) | |
| parent | arm64/fpsimd: Clarify the purpose of using last in fpsimd_save() (diff) | |
| download | linux-64330073b8efe9ea6ccbd451144ceb7178b54d04.tar.xz linux-64330073b8efe9ea6ccbd451144ceb7178b54d04.zip | |
Merge branch kvm-arm64/fpsimd-doc into kvmarm-master/next
* kvm-arm64/fpsimd-doc:
: .
: FPSIMD documentation update, courtesy of Mark Brown
: .
arm64/fpsimd: Clarify the purpose of using last in fpsimd_save()
KVM: arm64: Add some more comments in kvm_hyp_handle_fpsimd()
KVM: arm64: Add comments for context flush and sync callbacks
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/fpsimd.c | 14 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/include/hyp/switch.h | 4 |
2 files changed, 14 insertions, 4 deletions
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 2f48fd362a8c..397fdac75cb1 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -84,6 +84,11 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED; } +/* + * Called just before entering the guest once we are no longer + * preemptable. Syncs the host's TIF_FOREIGN_FPSTATE with the KVM + * mirror of the flag used by the hypervisor. + */ void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu) { if (test_thread_flag(TIF_FOREIGN_FPSTATE)) @@ -93,10 +98,11 @@ void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu) } /* - * 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 - * so that they will be written back if the kernel clobbers them due to - * kernel-mode NEON before re-entry into the guest. + * Called just after exiting the guest. 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 so that they will be + * written back if the kernel clobbers them due to kernel-mode NEON + * before re-entry into the guest. */ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) { diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 701cfb964905..667654bd3734 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -173,6 +173,8 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) return false; /* Valid trap. Switch the context: */ + + /* First disable enough traps to allow us to update the registers */ if (has_vhe()) { reg = CPACR_EL1_FPEN; if (sve_guest) @@ -188,11 +190,13 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) } isb(); + /* Write out the host state if it's in the registers */ if (vcpu->arch.flags & KVM_ARM64_FP_HOST) { __fpsimd_save_state(vcpu->arch.host_fpsimd_state); vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; } + /* Restore the guest state */ if (sve_guest) __hyp_sve_restore_guest(vcpu); else |