From dc4fbba11e4661a6a77a1f89ba32f9082e6395ff Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Thu, 29 Oct 2015 11:44:05 +1100 Subject: powerpc: Create disable_kernel_{fp,altivec,vsx,spe}() The enable_kernel_*() functions leave the relevant MSR bits enabled until we exit the kernel sometime later. Create disable versions that wrap the kernel use of FP, Altivec VSX or SPE. While we don't want to disable it normally for performance reasons (MSR writes are slow), it will be used for a debug boot option that does this and catches bad uses in other areas of the kernel. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman --- arch/powerpc/kvm/book3s_paired_singles.c | 1 + arch/powerpc/kvm/book3s_pr.c | 4 ++++ arch/powerpc/kvm/booke.c | 4 ++++ 3 files changed, 9 insertions(+) (limited to 'arch/powerpc/kvm') diff --git a/arch/powerpc/kvm/book3s_paired_singles.c b/arch/powerpc/kvm/book3s_paired_singles.c index a759d9adb0b6..eab96cfe82fa 100644 --- a/arch/powerpc/kvm/book3s_paired_singles.c +++ b/arch/powerpc/kvm/book3s_paired_singles.c @@ -1265,6 +1265,7 @@ int kvmppc_emulate_paired_single(struct kvm_run *run, struct kvm_vcpu *vcpu) if (rcomp) kvmppc_set_cr(vcpu, cr); + disable_kernel_fp(); preempt_enable(); return emulated; diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 64891b081ad5..49f5dad1bd45 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -751,6 +751,7 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr, preempt_disable(); enable_kernel_fp(); load_fp_state(&vcpu->arch.fp); + disable_kernel_fp(); t->fp_save_area = &vcpu->arch.fp; preempt_enable(); } @@ -760,6 +761,7 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr, preempt_disable(); enable_kernel_altivec(); load_vr_state(&vcpu->arch.vr); + disable_kernel_altivec(); t->vr_save_area = &vcpu->arch.vr; preempt_enable(); #endif @@ -788,6 +790,7 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu) preempt_disable(); enable_kernel_fp(); load_fp_state(&vcpu->arch.fp); + disable_kernel_fp(); preempt_enable(); } #ifdef CONFIG_ALTIVEC @@ -795,6 +798,7 @@ static void kvmppc_handle_lost_ext(struct kvm_vcpu *vcpu) preempt_disable(); enable_kernel_altivec(); load_vr_state(&vcpu->arch.vr); + disable_kernel_altivec(); preempt_enable(); } #endif diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index fd5875179e5c..778ef86e187e 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -98,6 +98,7 @@ void kvmppc_vcpu_disable_spe(struct kvm_vcpu *vcpu) preempt_disable(); enable_kernel_spe(); kvmppc_save_guest_spe(vcpu); + disable_kernel_spe(); vcpu->arch.shadow_msr &= ~MSR_SPE; preempt_enable(); } @@ -107,6 +108,7 @@ static void kvmppc_vcpu_enable_spe(struct kvm_vcpu *vcpu) preempt_disable(); enable_kernel_spe(); kvmppc_load_guest_spe(vcpu); + disable_kernel_spe(); vcpu->arch.shadow_msr |= MSR_SPE; preempt_enable(); } @@ -141,6 +143,7 @@ static inline void kvmppc_load_guest_fp(struct kvm_vcpu *vcpu) if (!(current->thread.regs->msr & MSR_FP)) { enable_kernel_fp(); load_fp_state(&vcpu->arch.fp); + disable_kernel_fp(); current->thread.fp_save_area = &vcpu->arch.fp; current->thread.regs->msr |= MSR_FP; } @@ -182,6 +185,7 @@ static inline void kvmppc_load_guest_altivec(struct kvm_vcpu *vcpu) if (!(current->thread.regs->msr & MSR_VEC)) { enable_kernel_altivec(); load_vr_state(&vcpu->arch.vr); + disable_kernel_altivec(); current->thread.vr_save_area = &vcpu->arch.vr; current->thread.regs->msr |= MSR_VEC; } -- cgit v1.2.1 From c208505900b232ecdc81dee54cb3a032e75d88d6 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Thu, 29 Oct 2015 11:44:08 +1100 Subject: powerpc: create giveup_all() Create a single function that gives everything up (FP, VMX, VSX, SPE). Doing this all at once means we only do one MSR write. A context switch microbenchmark using yield(): http://ozlabs.org/~anton/junkcode/context_switch2.c ./context_switch2 --test=yield --fp --altivec --vector 0 0 shows an improvement of 3% on POWER8. Signed-off-by: Anton Blanchard [mpe: giveup_all() needs to be EXPORT_SYMBOL'ed] Signed-off-by: Michael Ellerman --- arch/powerpc/kvm/book3s_pr.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) (limited to 'arch/powerpc/kvm') diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 49f5dad1bd45..a78e0e6bd932 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1490,21 +1490,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) goto out; /* interrupts now hard-disabled */ - /* Save FPU state in thread_struct */ - if (current->thread.regs->msr & MSR_FP) - giveup_fpu(current); - -#ifdef CONFIG_ALTIVEC - /* Save Altivec state in thread_struct */ - if (current->thread.regs->msr & MSR_VEC) - giveup_altivec(current); -#endif - -#ifdef CONFIG_VSX - /* Save VSX state in thread_struct */ - if (current->thread.regs->msr & MSR_VSX) - __giveup_vsx(current); -#endif + /* Save FPU, Altivec and VSX state */ + giveup_all(current); /* Preload FPU if it's enabled */ if (kvmppc_get_msr(vcpu) & MSR_FP) -- cgit v1.2.1 From 579e633e764e6e5f7784b74e7df3e81fe11f40de Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Thu, 29 Oct 2015 11:44:09 +1100 Subject: powerpc: create flush_all_to_thread() Create a single function that flushes everything (FP, VMX, VSX, SPE). Doing this all at once means we only do one MSR write. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman --- arch/powerpc/kvm/book3s_hv.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/kvm') diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 54b45b73195f..8e694707bc56 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -2700,9 +2700,8 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) goto out; } - flush_fp_to_thread(current); - flush_altivec_to_thread(current); - flush_vsx_to_thread(current); + flush_all_to_thread(current); + vcpu->arch.wqp = &vcpu->arch.vcore->wq; vcpu->arch.pgdir = current->mm->pgd; vcpu->arch.state = KVMPPC_VCPU_BUSY_IN_HOST; -- cgit v1.2.1