On 06/03/2013 03:54:26 PM, Mihai Caraman wrote:
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
Why not use kvmppc_supports_altivec()? In fact, there's nothing
KVM-specific about these functions...
+/*
+ * 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;
+}
Whitespace
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;
The distinction between how you're handling SPE and Altivec here
doesn't really have anything to do with SPE versus Altivec -- it's
PR-mode versus HV-mode.
@@ -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);
}
}
Why do you need to call an Altivec function here if we don't need to
call an ordinary FPU function here?
-Scott
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