KVM Book3E FPU support gracefully reuse host infrastructure so we do the
same for AltiVec. To keep AltiVec lazy call kvmppc_load_guest_altivec()
just when returning to guest instead of each sched in.
Signed-off-by: Mihai Caraman <mihai.caraman@xxxxxxxxxxxxx>
---
arch/powerpc/kvm/booke.c | 74 +++++++++++++++++++++++++++++++++++++++++++-
arch/powerpc/kvm/e500mc.c | 8 +++++
2 files changed, 80 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index c08b04b..01eb635 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -134,6 +134,23 @@ static void kvmppc_vcpu_sync_fpu(struct kvm_vcpu *vcpu)
}
/*
+ * Simulate AltiVec unavailable fault to load guest state
+ * from thread to AltiVec unit.
+ * It requires to be called with preemption disabled.
+ */
+static inline void kvmppc_load_guest_altivec(struct kvm_vcpu *vcpu)
+{
+#ifdef CONFIG_ALTIVEC
+ if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
+ if (!(current->thread.regs->msr & MSR_VEC)) {
+ load_up_altivec(NULL);
+ current->thread.regs->msr |= MSR_VEC;
+ }
+ }
+#endif
+}
+
+/*
* Helper function for "full" MSR writes. No need to call this if only
* EE/CE/ME/DE/RI are changing.
*/
@@ -661,6 +678,12 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
u64 fpr[32];
#endif
+#ifdef CONFIG_ALTIVEC
+ vector128 vr[32];
+ vector128 vscr;
+ int used_vr = 0;
+#endif
+
if (!vcpu->arch.sane) {
kvm_run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
return -EINVAL;
@@ -699,6 +722,22 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
kvmppc_load_guest_fp(vcpu);
#endif
+#ifdef CONFIG_ALTIVEC
+ if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
+ /* Save userspace VEC state in stack */
+ enable_kernel_altivec();
+ memcpy(vr, current->thread.vr, sizeof(current->thread.vr));
+ vscr = current->thread.vscr;
+ used_vr = current->thread.used_vr;
+
+ /* Restore guest VEC state to thread */
+ memcpy(current->thread.vr, vcpu->arch.vr, sizeof(vcpu->arch.vr));
+ current->thread.vscr = vcpu->arch.vscr;
+
+ kvmppc_load_guest_altivec(vcpu);
+ }
+#endif
+
ret = __kvmppc_vcpu_run(kvm_run, vcpu);
/* No need for kvm_guest_exit. It's done in handle_exit.
@@ -719,6 +758,23 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
current->thread.fpexc_mode = fpexc_mode;
#endif
+#ifdef CONFIG_ALTIVEC
+ if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
+ /* Save AltiVec state to thread */
+ if (current->thread.regs->msr & MSR_VEC)
+ giveup_altivec(current);
+
+ /* Save guest state */
+ memcpy(vcpu->arch.vr, current->thread.vr, sizeof(vcpu->arch.vr));
+ vcpu->arch.vscr = current->thread.vscr;
+
+ /* Restore userspace state */
+ memcpy(current->thread.vr, vr, sizeof(current->thread.vr));
+ current->thread.vscr = vscr;
+ current->thread.used_vr = used_vr;
+ }
+#endif
+
out:
vcpu->mode = OUTSIDE_GUEST_MODE;
return ret;
@@ -822,6 +878,19 @@ static void kvmppc_restart_interrupt(struct kvm_vcpu *vcpu,
}
}
+/*
+ * Always returns true is AltiVec unit is present, see
+ * kvmppc_core_check_processor_compat().
+ */
+static inline bool kvmppc_supports_altivec(void)
+{
+#ifdef CONFIG_ALTIVEC
+ if (cpu_has_feature(CPU_FTR_ALTIVEC))
+ return true;
+#endif
+ return false;
+}
+
static inline bool kvmppc_supports_spe(void)
{
#ifdef CONFIG_SPE
@@ -947,7 +1016,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
*/
bool handled = false;
- if (kvmppc_supports_spe()) {
+ if (kvmppc_supports_altivec() || kvmppc_supports_spe()) {
#ifdef CONFIG_SPE
if (cpu_has_feature(CPU_FTR_SPE))
if (vcpu->arch.shared->msr & MSR_SPE) {
@@ -976,7 +1045,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
* The interrupt is shared, KVM support for the featured unit
* is detected at run-time.
*/
- if (kvmppc_supports_spe()) {
+ if (kvmppc_supports_altivec() || kvmppc_supports_spe()) {
kvmppc_booke_queue_irqprio(vcpu,
BOOKE_IRQPRIO_SPE_FP_DATA_ALTIVEC_ASSIST);
r = RESUME_GUEST;
@@ -1188,6 +1257,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV);
} else {
kvmppc_lazy_ee_enable();
+ kvmppc_load_guest_altivec(vcpu);
}
}
diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
index c3bdc0a..9d7f38e 100644
--- a/arch/powerpc/kvm/e500mc.c
+++ b/arch/powerpc/kvm/e500mc.c
@@ -172,8 +172,16 @@ int kvmppc_core_check_processor_compat(void)
r = 0;
else if (strcmp(cur_cpu_spec->cpu_name, "e5500") == 0)
r = 0;
+#ifdef CONFIG_ALTIVEC
+ /*
+ * Since guests have the priviledge to enable AltiVec, we need AltiVec
+ * support in the host to save/restore their context.
+ * Don't use CPU_FTR_ALTIVEC to identify cores with AltiVec unit
+ * because it's cleared in the absence of CONFIG_ALTIVEC!
+ */
else if (strcmp(cur_cpu_spec->cpu_name, "e6500") == 0)
r = 0;
+#endif
else
r = -ENOTSUPP;
--
1.7.4.1
--
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