[PATCH 17/56] KVM: PPC: e500mc: Add doorbell emulation support

Alexander Graf
2012-03-15T12:10:46Z

When one vcpu wants to kick another, it can issue a special IPI instruction
called msgsnd. This patch emulates this instruction, its clearing counterpart
and the infrastructure required to actually trigger that interrupt inside
a guest vcpu.

With this patch, SMP guests on e500mc work.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
arch/powerpc/include/asm/dbell.h | 2 +
arch/powerpc/kvm/booke.c | 2 +
arch/powerpc/kvm/e500_emulate.c | 68 ++++++++++++++++++++++++++++++++++++++
3 files changed, 72 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/dbell.h b/arch/powerpc/include/asm/dbell.h
index d7365b0..154c067 100644
--- a/arch/powerpc/include/asm/dbell.h
+++ b/arch/powerpc/include/asm/dbell.h
@@ -19,7 +19,9 @@

#define PPC_DBELL_MSG_BRDCAST (0x04000000)
#define PPC_DBELL_TYPE(x) (((x) & 0xf) << (63-36))
+#define PPC_DBELL_TYPE_MASK PPC_DBELL_TYPE(0xf)
#define PPC_DBELL_LPID(x) ((x) << (63 - 49))
+#define PPC_DBELL_PIR_MASK 0x3fff
enum ppc_dbell {
PPC_DBELL = 0, /* doorbell */
PPC_DBELL_CRIT = 1, /* critical doorbell */
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 0b77be1..85bd5b8 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -326,6 +326,7 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
int_class = INT_CLASS_NONCRIT;
break;
case BOOKE_IRQPRIO_CRITICAL:
+ case BOOKE_IRQPRIO_DBELL_CRIT:
allowed = vcpu->arch.shared->msr & MSR_CE;
allowed = allowed && !crit;
msr_mask = MSR_GS | MSR_ME;
@@ -342,6 +343,7 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
keep_irq = true;
/* fall through */
case BOOKE_IRQPRIO_EXTERNAL:
+ case BOOKE_IRQPRIO_DBELL:
allowed = vcpu->arch.shared->msr & MSR_EE;
allowed = allowed && !crit;
msr_mask = MSR_GS | MSR_CE | MSR_ME | MSR_DE;
diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c
index 98b6c1c..99155f8 100644
--- a/arch/powerpc/kvm/e500_emulate.c
+++ b/arch/powerpc/kvm/e500_emulate.c
@@ -14,16 +14,74 @@

#include <asm/kvm_ppc.h>
#include <asm/disassemble.h>
+#include <asm/dbell.h>

#include "booke.h"
#include "e500.h"

+#define XOP_MSGSND 206
+#define XOP_MSGCLR 238
#define XOP_TLBIVAX 786
#define XOP_TLBSX 914
#define XOP_TLBRE 946
#define XOP_TLBWE 978
#define XOP_TLBILX 18

+#ifdef CONFIG_KVM_E500MC
+static int dbell2prio(ulong param)
+{
+ int msg = param & PPC_DBELL_TYPE_MASK;
+ int prio = -1;
+
+ switch (msg) {
+ case PPC_DBELL_TYPE(PPC_DBELL):
+ prio = BOOKE_IRQPRIO_DBELL;
+ break;
+ case PPC_DBELL_TYPE(PPC_DBELL_CRIT):
+ prio = BOOKE_IRQPRIO_DBELL_CRIT;
+ break;
+ default:
+ break;
+ }
+
+ return prio;
+}
+
+static int kvmppc_e500_emul_msgclr(struct kvm_vcpu *vcpu, int rb)
+{
+ ulong param = vcpu->arch.gpr[rb];
+ int prio = dbell2prio(param);
+
+ if (prio < 0)
+ return EMULATE_FAIL;
+
+ clear_bit(prio, &vcpu->arch.pending_exceptions);
+ return EMULATE_DONE;
+}
+
+static int kvmppc_e500_emul_msgsnd(struct kvm_vcpu *vcpu, int rb)
+{
+ ulong param = vcpu->arch.gpr[rb];
+ int prio = dbell2prio(rb);
+ int pir = param & PPC_DBELL_PIR_MASK;
+ int i;
+ struct kvm_vcpu *cvcpu;
+
+ if (prio < 0)
+ return EMULATE_FAIL;
+
+ kvm_for_each_vcpu(i, cvcpu, vcpu->kvm) {
+ int cpir = cvcpu->arch.shared->pir;
+ if ((param & PPC_DBELL_MSG_BRDCAST) || (cpir = pir)) {
+ set_bit(prio, &cvcpu->arch.pending_exceptions);
+ kvm_vcpu_kick(cvcpu);
+ }
+ }
+
+ return EMULATE_DONE;
+}
+#endif
+
int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
unsigned int inst, int *advance)
{
@@ -36,6 +94,16 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
case 31:
switch (get_xop(inst)) {

+#ifdef CONFIG_KVM_E500MC
+ case XOP_MSGSND:
+ emulated = kvmppc_e500_emul_msgsnd(vcpu, get_rb(inst));
+ break;
+
+ case XOP_MSGCLR:
+ emulated = kvmppc_e500_emul_msgclr(vcpu, get_rb(inst));
+ break;
+#endif
+
case XOP_TLBRE:
emulated = kvmppc_e500_emul_tlbre(vcpu);
break;
--
1.6.0.2