| Message ID | 20211013155831.943476-4-qperret@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: Implement unshare hypercall for pkvm | expand |
On Wed, 13 Oct 2021 16:58:18 +0100, Quentin Perret <qperret@google.com> wrote: > > We currently map the SVE state into the hypervisor stage-1 on VCPU_RUN, > when the vCPU thread's PID has changed. However, this only needs to be > done during the first VCPU_RUN as the SVE state doesn't depend on > thread-specific data, so move the create_hyp_mapping() call to > kvm_vcpu_first_run_init(). > > Suggested-by: Marc Zyngier <maz@kernel.org> > Signed-off-by: Quentin Perret <qperret@google.com> > --- > arch/arm64/kvm/arm.c | 12 ++++++++++++ > arch/arm64/kvm/fpsimd.c | 11 ----------- > 2 files changed, 12 insertions(+), 11 deletions(-) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index fe102cd2e518..c33d8c073820 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -618,6 +618,18 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) > if (ret) > return ret; > > + if (vcpu->arch.sve_state) { > + void *sve_end; > + > + sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu); > + > + ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end, > + PAGE_HYP); > + if (ret) > + return ret; > + } > + > + > ret = kvm_arm_pmu_v3_enable(vcpu); > > return ret; > diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c > index 5621020b28de..62c0d78da7be 100644 > --- a/arch/arm64/kvm/fpsimd.c > +++ b/arch/arm64/kvm/fpsimd.c > @@ -43,17 +43,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) > if (ret) > goto error; > > - if (vcpu->arch.sve_state) { > - void *sve_end; > - > - sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu); > - > - ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end, > - PAGE_HYP); > - if (ret) > - goto error; > - } > - > vcpu->arch.host_thread_info = kern_hyp_va(ti); > vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); > error: I actually ended-up implementing a similar patch as part of my 'first run' series[1], though I moved the mapping to the point where we finalise the vcpu as that's where the allocation takes place. Do you see any potential issue with that approach? Thanks, M. [1] https://lore.kernel.org/r/20211015090822.2994920-2-maz@kernel.org
On Saturday 16 Oct 2021 at 12:04:15 (+0100), Marc Zyngier wrote: > I actually ended-up implementing a similar patch as part of my 'first > run' series[1], though I moved the mapping to the point where we > finalise the vcpu as that's where the allocation takes place. > > Do you see any potential issue with that approach? Nope, and in fact I think your patch should allow to simplify a bit kvm_arm_vcpu_destroy() for me, as checking arch.sve_state != NULL would now be sufficient to know if the sve state has been shared -- checking arch.has_run_once is no longer needed. I'll base v2 on this. Thanks! Quentin
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index fe102cd2e518..c33d8c073820 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -618,6 +618,18 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu) if (ret) return ret; + if (vcpu->arch.sve_state) { + void *sve_end; + + sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu); + + ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end, + PAGE_HYP); + if (ret) + return ret; + } + + ret = kvm_arm_pmu_v3_enable(vcpu); return ret; diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 5621020b28de..62c0d78da7be 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -43,17 +43,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) if (ret) goto error; - if (vcpu->arch.sve_state) { - void *sve_end; - - sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu); - - ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end, - PAGE_HYP); - if (ret) - goto error; - } - vcpu->arch.host_thread_info = kern_hyp_va(ti); vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); error:
We currently map the SVE state into the hypervisor stage-1 on VCPU_RUN, when the vCPU thread's PID has changed. However, this only needs to be done during the first VCPU_RUN as the SVE state doesn't depend on thread-specific data, so move the create_hyp_mapping() call to kvm_vcpu_first_run_init(). Suggested-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Quentin Perret <qperret@google.com> --- arch/arm64/kvm/arm.c | 12 ++++++++++++ arch/arm64/kvm/fpsimd.c | 11 ----------- 2 files changed, 12 insertions(+), 11 deletions(-)