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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2018-01-12 13:37:13 +1100
committerPaul Mackerras <paulus@ozlabs.org>2018-01-19 12:10:21 +1100
commit2267ea7661798a42f0da648a2970e2a03f4bc370 (patch)
treec81a43b275313a69d33b1f8276255739114863d0
parentbf4159da4751ab8eea43ca6e7c49193dbce8398c (diff)
KVM: PPC: Book3S HV: Don't use existing "prodded" flag for XIVE escalations
The prodded flag is only cleared at the beginning of H_CEDE, so every time we have an escalation, we will cause the *next* H_CEDE to return immediately. Instead use a dedicated "irq_pending" flag to indicate that a guest interrupt is pending for the VCPU. We don't reuse the existing exception bitmap so as to avoid expensive atomic ops. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
-rw-r--r--arch/powerpc/include/asm/kvm_host.h1
-rw-r--r--arch/powerpc/kernel/asm-offsets.c1
-rw-r--r--arch/powerpc/kvm/book3s_hv.c2
-rw-r--r--arch/powerpc/kvm/book3s_hv_rmhandlers.S10
-rw-r--r--arch/powerpc/kvm/book3s_xive.c3
5 files changed, 14 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 3aa5b577cd60..bfe51356af5e 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -709,6 +709,7 @@ struct kvm_vcpu_arch {
u8 ceded;
u8 prodded;
u8 doorbell_request;
+ u8 irq_pending; /* Used by XIVE to signal pending guest irqs */
u32 last_inst;
struct swait_queue_head *wqp;
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 6b958414b4e0..825089cf3e23 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -514,6 +514,7 @@ int main(void)
OFFSET(VCPU_PENDING_EXC, kvm_vcpu, arch.pending_exceptions);
OFFSET(VCPU_CEDED, kvm_vcpu, arch.ceded);
OFFSET(VCPU_PRODDED, kvm_vcpu, arch.prodded);
+ OFFSET(VCPU_IRQ_PENDING, kvm_vcpu, arch.irq_pending);
OFFSET(VCPU_DBELL_REQ, kvm_vcpu, arch.doorbell_request);
OFFSET(VCPU_MMCR, kvm_vcpu, arch.mmcr);
OFFSET(VCPU_PMC, kvm_vcpu, arch.pmc);
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 76cf48051eb3..e5f81fc108e0 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -2999,7 +2999,7 @@ static inline bool xive_interrupt_pending(struct kvm_vcpu *vcpu)
{
if (!xive_enabled())
return false;
- return vcpu->arch.xive_saved_state.pipr <
+ return vcpu->arch.irq_pending || vcpu->arch.xive_saved_state.pipr <
vcpu->arch.xive_saved_state.cppr;
}
#else
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 7daf21be33d0..34dbab7deb39 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1035,6 +1035,16 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300)
li r9, 1
stw r9, VCPU_XIVE_PUSHED(r4)
eieio
+
+ /*
+ * We clear the irq_pending flag. There is a small chance of a
+ * race vs. the escalation interrupt happening on another
+ * processor setting it again, but the only consequence is to
+ * cause a spurrious wakeup on the next H_CEDE which is not an
+ * issue.
+ */
+ li r0,0
+ stb r0, VCPU_IRQ_PENDING(r4)
no_xive:
#endif /* CONFIG_KVM_XICS */
diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index a102efeabf05..eef9ccafdc09 100644
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -84,8 +84,7 @@ static irqreturn_t xive_esc_irq(int irq, void *data)
{
struct kvm_vcpu *vcpu = data;
- /* We use the existing H_PROD mechanism to wake up the target */
- vcpu->arch.prodded = 1;
+ vcpu->arch.irq_pending = 1;
smp_mb();
if (vcpu->arch.ceded)
kvmppc_fast_vcpu_kick(vcpu);