diff options
Diffstat (limited to 'arch/arm64/kvm/fpsimd.c')
| -rw-r--r-- | arch/arm64/kvm/fpsimd.c | 100 |
1 files changed, 56 insertions, 44 deletions
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c index 826307e19e3a..ea5484ce1f3b 100644 --- a/arch/arm64/kvm/fpsimd.c +++ b/arch/arm64/kvm/fpsimd.c @@ -14,19 +14,6 @@ #include <asm/kvm_mmu.h> #include <asm/sysreg.h> -void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu) -{ - struct task_struct *p = vcpu->arch.parent_task; - struct user_fpsimd_state *fpsimd; - - if (!is_protected_kvm_enabled() || !p) - return; - - fpsimd = &p->thread.uw.fpsimd_state; - kvm_unshare_hyp(fpsimd, fpsimd + 1); - put_task_struct(p); -} - /* * Called on entry to KVM_RUN unless this vcpu previously ran at least * once and the most recent prior KVM_RUN for this vcpu was called from @@ -38,30 +25,18 @@ void kvm_vcpu_unshare_task_fp(struct kvm_vcpu *vcpu) */ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) { - int ret; - struct user_fpsimd_state *fpsimd = ¤t->thread.uw.fpsimd_state; + int ret; - kvm_vcpu_unshare_task_fp(vcpu); + /* pKVM has its own tracking of the host fpsimd state. */ + if (is_protected_kvm_enabled()) + return 0; /* Make sure the host task fpsimd state is visible to hyp: */ ret = kvm_share_hyp(fpsimd, fpsimd + 1); if (ret) return ret; - vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd); - - /* - * We need to keep current's task_struct pinned until its data has been - * unshared with the hypervisor to make sure it is not re-used by the - * kernel and donated to someone else while already shared -- see - * kvm_vcpu_unshare_task_fp() for the matching put_task_struct(). - */ - if (is_protected_kvm_enabled()) { - get_task_struct(current); - vcpu->arch.parent_task = current; - } - return 0; } @@ -86,7 +61,9 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) * guest in kvm_arch_vcpu_ctxflush_fp() and override this to * FP_STATE_FREE if the flag set. */ - vcpu->arch.fp_state = FP_STATE_HOST_OWNED; + *host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED; + *host_data_ptr(fpsimd_state) = kern_hyp_va(¤t->thread.uw.fpsimd_state); + *host_data_ptr(fpmr_ptr) = kern_hyp_va(¤t->thread.uw.fpmr); vcpu_clear_flag(vcpu, HOST_SVE_ENABLED); if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN) @@ -110,10 +87,17 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) * been saved, this is very unlikely to happen. */ if (read_sysreg_s(SYS_SVCR) & (SVCR_SM_MASK | SVCR_ZA_MASK)) { - vcpu->arch.fp_state = FP_STATE_FREE; + *host_data_ptr(fp_owner) = FP_STATE_FREE; fpsimd_save_and_flush_cpu_state(); } } + + /* + * If normal guests gain SME support, maintain this behavior for pKVM + * guests, which don't support SME. + */ + WARN_ON(is_protected_kvm_enabled() && system_supports_sme() && + read_sysreg_s(SYS_SVCR)); } /* @@ -126,7 +110,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu) { if (test_thread_flag(TIF_FOREIGN_FPSTATE)) - vcpu->arch.fp_state = FP_STATE_FREE; + *host_data_ptr(fp_owner) = FP_STATE_FREE; } /* @@ -142,8 +126,7 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) WARN_ON_ONCE(!irqs_disabled()); - if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) { - + if (guest_owns_fp_regs()) { /* * Currently we do not support SME guests so SVCR is * always 0 and we just need a variable to point to. @@ -152,8 +135,8 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) fp_state.sve_state = vcpu->arch.sve_state; fp_state.sve_vl = vcpu->arch.sve_max_vl; fp_state.sme_state = NULL; - fp_state.svcr = &vcpu->arch.svcr; - fp_state.fpmr = &vcpu->arch.fpmr; + fp_state.svcr = &__vcpu_sys_reg(vcpu, SVCR); + fp_state.fpmr = &__vcpu_sys_reg(vcpu, FPMR); fp_state.fp_type = &vcpu->arch.fp_type; if (vcpu_has_sve(vcpu)) @@ -186,9 +169,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) if (has_vhe() && system_supports_sme()) { /* Also restore EL0 state seen on entry */ if (vcpu_get_flag(vcpu, HOST_SME_ENABLED)) - sysreg_clear_set(CPACR_EL1, 0, - CPACR_EL1_SMEN_EL0EN | - CPACR_EL1_SMEN_EL1EN); + sysreg_clear_set(CPACR_EL1, 0, CPACR_ELx_SMEN); else sysreg_clear_set(CPACR_EL1, CPACR_EL1_SMEN_EL0EN, @@ -196,16 +177,47 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) isb(); } - if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) { + if (guest_owns_fp_regs()) { if (vcpu_has_sve(vcpu)) { - __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR); - - /* Restore the VL that was saved when bound to the CPU */ - if (!has_vhe()) + u64 zcr = read_sysreg_el1(SYS_ZCR); + + /* + * If the vCPU is in the hyp context then ZCR_EL1 is + * loaded with its vEL2 counterpart. + */ + __vcpu_sys_reg(vcpu, vcpu_sve_zcr_elx(vcpu)) = zcr; + + /* + * Restore the VL that was saved when bound to the CPU, + * which is the maximum VL for the guest. Because the + * layout of the data when saving the sve state depends + * on the VL, we need to use a consistent (i.e., the + * maximum) VL. + * Note that this means that at guest exit ZCR_EL1 is + * not necessarily the same as on guest entry. + * + * ZCR_EL2 holds the guest hypervisor's VL when running + * a nested guest, which could be smaller than the + * max for the vCPU. Similar to above, we first need to + * switch to a VL consistent with the layout of the + * vCPU's SVE state. KVM support for NV implies VHE, so + * using the ZCR_EL1 alias is safe. + */ + if (!has_vhe() || (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu))) sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL1); } + /* + * Flush (save and invalidate) the fpsimd/sve state so that if + * the host tries to use fpsimd/sve, it's not using stale data + * from the guest. + * + * Flushing the state sets the TIF_FOREIGN_FPSTATE bit for the + * context unconditionally, in both nVHE and VHE. This allows + * the kernel to restore the fpsimd/sve state, including ZCR_EL1 + * when needed. + */ fpsimd_save_and_flush_cpu_state(); } else if (has_vhe() && system_supports_sve()) { /* |