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KVM: ppc: guest breakpoint support

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Allow host userspace to program hardware debug registers to set breakpoints
inside guests.

Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
This commit is contained in:
Hollis Blanchard 2008-07-25 13:54:49 -05:00 committed by Avi Kivity
parent b5e2fec0eb
commit 6a0ab738ef
4 changed files with 113 additions and 2 deletions
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5
arch/powerpc/include/asm/kvm_host.h
View file

@ -86,6 +86,11 @@ struct kvm_vcpu_arch {
u32 host_stack;
u32 host_pid;
u32 host_dbcr0;
u32 host_dbcr1;
u32 host_dbcr2;
u32 host_iac[4];
u32 host_msr;
u64 fpr[32];
u32 gpr[32];

15
arch/powerpc/kvm/booke_guest.c
View file

@ -410,6 +410,21 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
break;
}
case BOOKE_INTERRUPT_DEBUG: {
u32 dbsr;
vcpu->arch.pc = mfspr(SPRN_CSRR0);
/* clear IAC events in DBSR register */
dbsr = mfspr(SPRN_DBSR);
dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;
mtspr(SPRN_DBSR, dbsr);
run->exit_reason = KVM_EXIT_DEBUG;
r = RESUME_HOST;
break;
}
default:
printk(KERN_EMERG "exit_nr %d\n", exit_nr);
BUG();

11
arch/powerpc/kvm/booke_interrupts.S
View file

@ -42,7 +42,8 @@
#define HOST_STACK_LR (HOST_STACK_SIZE + 4) /* In caller stack frame. */
#define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
(1<<BOOKE_INTERRUPT_DTLB_MISS) | \
(1<<BOOKE_INTERRUPT_DEBUG))
#define NEED_DEAR_MASK ((1<<BOOKE_INTERRUPT_DATA_STORAGE) | \
(1<<BOOKE_INTERRUPT_DTLB_MISS))
@ -431,6 +432,14 @@ lightweight_exit:
oris r3, r3, KVMPPC_MSR_MASK@h
ori r3, r3, KVMPPC_MSR_MASK@l
mtsrr1 r3
/* Clear any debug events which occurred since we disabled MSR[DE].
* XXX This gives us a 3-instruction window in which a breakpoint
* intended for guest context could fire in the host instead. */
lis r3, 0xffff
ori r3, r3, 0xffff
mtspr SPRN_DBSR, r3
lwz r3, VCPU_GPR(r3)(r4)
lwz r4, VCPU_GPR(r4)(r4)
rfi

84
arch/powerpc/kvm/powerpc.c
View file

@ -239,18 +239,100 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
{
}
/* Note: clearing MSR[DE] just means that the debug interrupt will not be
* delivered *immediately*. Instead, it simply sets the appropriate DBSR bits.
* If those DBSR bits are still set when MSR[DE] is re-enabled, the interrupt
* will be delivered as an "imprecise debug event" (which is indicated by
* DBSR[IDE].
*/
static void kvmppc_disable_debug_interrupts(void)
{
mtmsr(mfmsr() & ~MSR_DE);
}
static void kvmppc_restore_host_debug_state(struct kvm_vcpu *vcpu)
{
kvmppc_disable_debug_interrupts();
mtspr(SPRN_IAC1, vcpu->arch.host_iac[0]);
mtspr(SPRN_IAC2, vcpu->arch.host_iac[1]);
mtspr(SPRN_IAC3, vcpu->arch.host_iac[2]);
mtspr(SPRN_IAC4, vcpu->arch.host_iac[3]);
mtspr(SPRN_DBCR1, vcpu->arch.host_dbcr1);
mtspr(SPRN_DBCR2, vcpu->arch.host_dbcr2);
mtspr(SPRN_DBCR0, vcpu->arch.host_dbcr0);
mtmsr(vcpu->arch.host_msr);
}
static void kvmppc_load_guest_debug_registers(struct kvm_vcpu *vcpu)
{
struct kvm_guest_debug *dbg = &vcpu->guest_debug;
u32 dbcr0 = 0;
vcpu->arch.host_msr = mfmsr();
kvmppc_disable_debug_interrupts();
/* Save host debug register state. */
vcpu->arch.host_iac[0] = mfspr(SPRN_IAC1);
vcpu->arch.host_iac[1] = mfspr(SPRN_IAC2);
vcpu->arch.host_iac[2] = mfspr(SPRN_IAC3);
vcpu->arch.host_iac[3] = mfspr(SPRN_IAC4);
vcpu->arch.host_dbcr0 = mfspr(SPRN_DBCR0);
vcpu->arch.host_dbcr1 = mfspr(SPRN_DBCR1);
vcpu->arch.host_dbcr2 = mfspr(SPRN_DBCR2);
/* set registers up for guest */
if (dbg->bp[0]) {
mtspr(SPRN_IAC1, dbg->bp[0]);
dbcr0 |= DBCR0_IAC1 | DBCR0_IDM;
}
if (dbg->bp[1]) {
mtspr(SPRN_IAC2, dbg->bp[1]);
dbcr0 |= DBCR0_IAC2 | DBCR0_IDM;
}
if (dbg->bp[2]) {
mtspr(SPRN_IAC3, dbg->bp[2]);
dbcr0 |= DBCR0_IAC3 | DBCR0_IDM;
}
if (dbg->bp[3]) {
mtspr(SPRN_IAC4, dbg->bp[3]);
dbcr0 |= DBCR0_IAC4 | DBCR0_IDM;
}
mtspr(SPRN_DBCR0, dbcr0);
mtspr(SPRN_DBCR1, 0);
mtspr(SPRN_DBCR2, 0);
}
void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
if (vcpu->guest_debug.enabled)
kvmppc_load_guest_debug_registers(vcpu);
}
void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
if (vcpu->guest_debug.enabled)
kvmppc_restore_host_debug_state(vcpu);
}
int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
struct kvm_debug_guest *dbg)
{
return -ENOTSUPP;
int i;
vcpu->guest_debug.enabled = dbg->enabled;
if (vcpu->guest_debug.enabled) {
for (i=0; i < ARRAY_SIZE(vcpu->guest_debug.bp); i++) {
if (dbg->breakpoints[i].enabled)
vcpu->guest_debug.bp[i] = dbg->breakpoints[i].address;
else
vcpu->guest_debug.bp[i] = 0;
}
}
return 0;
}
static void kvmppc_complete_dcr_load(struct kvm_vcpu *vcpu,