From: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx>
This patch adds the debug stub support on booke/bookehv.
Now QEMU debug stub can use hw breakpoint, watchpoint and
software breakpoint to debug guest.
Debug registers are saved/restored on vcpu_put()/vcpu_get().
Also the debug registers are saved restored only if guest is using
debug resources.
Signed-off-by: Bharat Bhushan <bharat.bhushan@xxxxxxxxxxxxx>
---
v2:
- save/restore in vcpu_get()/vcpu_put()
- some more minor cleanup based on review comments.
arch/powerpc/include/asm/kvm_host.h | 10 ++
arch/powerpc/include/uapi/asm/kvm.h | 22 +++-
arch/powerpc/kvm/booke.c | 252 ++++++++++++++++++++++++++++++++---
arch/powerpc/kvm/e500_emulate.c | 10 ++
4 files changed, 272 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index f4ba881..8571952 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -504,7 +504,17 @@ struct kvm_vcpu_arch {
u32 mmucfg;
u32 epr;
u32 crit_save;
+ /* guest debug registers*/
struct kvmppc_booke_debug_reg dbg_reg;
+ /* shadow debug registers */
+ struct kvmppc_booke_debug_reg shadow_dbg_reg;
+ /* host debug registers*/
+ struct kvmppc_booke_debug_reg host_dbg_reg;
+ /*
+ * Flag indicating that debug registers are used by guest
+ * and requires save restore.
+ */
+ bool debug_save_restore;
#endif
gpa_t paddr_accessed;
gva_t vaddr_accessed;
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 15f9a00..d7ce449 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -25,6 +25,7 @@
/* Select powerpc specific features in <linux/kvm.h> */
#define __KVM_HAVE_SPAPR_TCE
#define __KVM_HAVE_PPC_SMT
+#define __KVM_HAVE_GUEST_DEBUG
struct kvm_regs {
__u64 pc;
@@ -267,7 +268,24 @@ struct kvm_fpu {
__u64 fpr[32];
};
+/*
+ * Defines for h/w breakpoint, watchpoint (read, write or both) and
+ * software breakpoint.
+ * These are used as "type" in KVM_SET_GUEST_DEBUG ioctl and "status"
+ * for KVM_DEBUG_EXIT.
+ */
+#define KVMPPC_DEBUG_NONE 0x0
+#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
+#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
+#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
struct kvm_debug_exit_arch {
+ __u64 address;
+ /*
+ * exiting to userspace because of h/w breakpoint, watchpoint
+ * (read, write or both) and software breakpoint.
+ */
+ __u32 status;
+ __u32 reserved;
};
/* for KVM_SET_GUEST_DEBUG */
@@ -279,10 +297,6 @@ struct kvm_guest_debug_arch {
* Type denotes h/w breakpoint, read watchpoint, write
* watchpoint or watchpoint (both read and write).
*/
-#define KVMPPC_DEBUG_NOTYPE 0x0
-#define KVMPPC_DEBUG_BREAKPOINT (1UL << 1)
-#define KVMPPC_DEBUG_WATCH_WRITE (1UL << 2)
-#define KVMPPC_DEBUG_WATCH_READ (1UL << 3)
__u32 type;
__u32 reserved;
} bp[16];
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 1de93a8..bf20056 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -133,6 +133,30 @@ static void kvmppc_vcpu_sync_fpu(struct kvm_vcpu *vcpu)
#endif
}
+static void kvmppc_vcpu_sync_debug(struct kvm_vcpu *vcpu)
+{
+ /* Synchronize guest's desire to get debug interrupts into shadow MSR */
+#ifndef CONFIG_KVM_BOOKE_HV
+ vcpu->arch.shadow_msr &= ~MSR_DE;
+ vcpu->arch.shadow_msr |= vcpu->arch.shared->msr & MSR_DE;
+#endif
+
+ /* Force enable debug interrupts when user space wants to debug */
+ if (vcpu->guest_debug) {
+#ifdef CONFIG_KVM_BOOKE_HV
+ /*
+ * Since there is no shadow MSR, sync MSR_DE into the guest
+ * visible MSR. Do not allow guest to change MSR[DE].
+ */
+ vcpu->arch.shared->msr |= MSR_DE;
+ mtspr(SPRN_MSRP, mfspr(SPRN_MSRP) | MSRP_DEP);
+#else
+ vcpu->arch.shadow_msr |= MSR_DE;
+ vcpu->arch.shared->msr &= ~MSR_DE;
+#endif
+ }
+}
+
/*
* Helper function for "full" MSR writes. No need to call this if only
* EE/CE/ME/DE/RI are changing.
@@ -150,6 +174,7 @@ void kvmppc_set_msr(struct kvm_vcpu *vcpu, u32 new_msr)
kvmppc_mmu_msr_notify(vcpu, old_msr);
kvmppc_vcpu_sync_spe(vcpu);
kvmppc_vcpu_sync_fpu(vcpu);
+ kvmppc_vcpu_sync_debug(vcpu);
}
static void kvmppc_booke_queue_irqprio(struct kvm_vcpu *vcpu,
@@ -736,6 +761,9 @@ static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
run->exit_reason = KVM_EXIT_DCR;
return RESUME_HOST;
+ case EMULATE_EXIT_USER:
+ return RESUME_HOST;
+
case EMULATE_FAIL:
printk(KERN_CRIT "%s: emulation at %lx failed (%08x)\n",
__func__, vcpu->arch.pc, vcpu->arch.last_inst);
@@ -751,6 +779,30 @@ static int emulation_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
}
}
+static int kvmppc_handle_debug(struct kvm_run *run, struct kvm_vcpu *vcpu)
+{
+ u32 dbsr = mfspr(SPRN_DBSR);
+ mtspr(SPRN_DBSR, dbsr);
+
+ run->debug.arch.status = 0;
+ run->debug.arch.address = vcpu->arch.pc;
+
+ if (dbsr & (DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4)) {
+ run->debug.arch.status |= KVMPPC_DEBUG_BREAKPOINT;
+ } else {
+ if (dbsr & (DBSR_DAC1W | DBSR_DAC2W))
+ run->debug.arch.status |= KVMPPC_DEBUG_WATCH_WRITE;
+ else if (dbsr & (DBSR_DAC1R | DBSR_DAC2R))
+ run->debug.arch.status |= KVMPPC_DEBUG_WATCH_READ;
+ if (dbsr & (DBSR_DAC1R | DBSR_DAC1W))
+ run->debug.arch.address = vcpu->arch.shadow_dbg_reg.dac[0];
+ else if (dbsr & (DBSR_DAC2R | DBSR_DAC2W))
+ run->debug.arch.address = vcpu->arch.shadow_dbg_reg.dac[1];
+ }
+
+ return RESUME_HOST;
+}
+
static void kvmppc_fill_pt_regs(struct pt_regs *regs)
{
ulong r1, ip, msr, lr;
@@ -1110,18 +1162,10 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu,
}
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 = kvmppc_handle_debug(run, vcpu);
+ if (r == RESUME_HOST)
+ run->exit_reason = KVM_EXIT_DEBUG;
kvmppc_account_exit(vcpu, DEBUG_EXITS);
- r = RESUME_HOST;
break;
}
@@ -1172,7 +1216,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
kvmppc_set_msr(vcpu, 0);
#ifndef CONFIG_KVM_BOOKE_HV
- vcpu->arch.shadow_msr = MSR_USER | MSR_DE | MSR_IS | MSR_DS;
+ vcpu->arch.shadow_msr = MSR_USER | MSR_IS | MSR_DS;
vcpu->arch.shadow_pid = 1;
vcpu->arch.shared->msr = 0;
#endif
@@ -1527,12 +1571,6 @@ int kvm_vcpu_ioctl_set_one_reg(struct kvm_vcpu *vcpu, struct kvm_one_reg *reg)
return r;
}
-int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
- struct kvm_guest_debug *dbg)
-{
- return -EINVAL;
-}
-
int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
return -ENOTSUPP;
@@ -1638,16 +1676,194 @@ void kvmppc_decrementer_func(unsigned long data)
kvmppc_set_tsr_bits(vcpu, TSR_DIS);
}
+static void kvmppc_booke_vcpu_put_debug_regs(struct kvm_vcpu *vcpu)
+{
+ if (!vcpu->arch.debug_save_restore)
+ return;
+
+ /* Restore Host Context. Disable all debug events First */
+ mtspr(SPRN_DBCR0, 0x0);
+ /* Disable pending debug event by Clearing DBSR */
+ mtspr(SPRN_DBSR, mfspr(SPRN_DBSR));
+
+ mtspr(SPRN_DBCR1, vcpu->arch.host_dbg_reg.dbcr1);
+ mtspr(SPRN_DBCR2, vcpu->arch.host_dbg_reg.dbcr2);
+#ifdef CONFIG_KVM_E500MC
+ mtspr(SPRN_DBCR4, vcpu->arch.host_dbg_reg.dbcr4);
+#endif
+ mtspr(SPRN_IAC1, vcpu->arch.host_dbg_reg.iac[0]);
+ mtspr(SPRN_IAC2, vcpu->arch.host_dbg_reg.iac[1]);
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ mtspr(SPRN_IAC3, vcpu->arch.host_dbg_reg.iac[2]);
+ mtspr(SPRN_IAC4, vcpu->arch.host_dbg_reg.iac[3]);
+#endif
+ mtspr(SPRN_DAC1, vcpu->arch.host_dbg_reg.dac[0]);
+ mtspr(SPRN_DAC2, vcpu->arch.host_dbg_reg.dac[1]);
+
+ /* Enable debug events after all other debug registers restored */
+ mtspr(SPRN_DBCR0, vcpu->arch.host_dbg_reg.dbcr0);
+
+ /* Host debug register are restored */
+ vcpu->arch.debug_save_restore = false;
+}
+
+static void kvmppc_booke_vcpu_load_debug_regs(struct kvm_vcpu *vcpu)
+{
+ /*
+ * Check whether guest still need debug resource, if not then there
+ * is no need to resotre guest context.
+ */
+ if (!vcpu->arch.shadow_dbg_reg.dbcr0)
+ return;
+
+ /*
+ * Save Host debug register only after restore. If host debug
+ * registers are saved and not restored then do not save again.
+ */
+ if (!vcpu->arch.debug_save_restore) {
+ /* Save Host context */
+ vcpu->arch.host_dbg_reg.dbcr0 = mfspr(SPRN_DBCR0);
+ vcpu->arch.host_dbg_reg.dbcr1 = mfspr(SPRN_DBCR1);
+ vcpu->arch.host_dbg_reg.dbcr2 = mfspr(SPRN_DBCR2);
+#ifdef CONFIG_KVM_E500MC
+ vcpu->arch.host_dbg_reg.dbcr4 = mfspr(SPRN_DBCR4);
+#endif
+ vcpu->arch.host_dbg_reg.iac[0] = mfspr(SPRN_IAC1);
+ vcpu->arch.host_dbg_reg.iac[1] = mfspr(SPRN_IAC2);
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ vcpu->arch.host_dbg_reg.iac[2] = mfspr(SPRN_IAC3);
+ vcpu->arch.host_dbg_reg.iac[3] = mfspr(SPRN_IAC4);
+#endif
+ vcpu->arch.host_dbg_reg.dac[0] = mfspr(SPRN_DAC1);
+ vcpu->arch.host_dbg_reg.dac[1] = mfspr(SPRN_DAC2);
+ vcpu->arch.debug_save_restore = true;
+ }
+
+ /* Restore Guest Context. Disable all debug events First */
+ mtspr(SPRN_DBCR0, 0x0);
+ /* Clear h/w DBSR */
+ mtspr(SPRN_DBSR, mfspr(SPRN_DBSR));
+
+ mtspr(SPRN_DBCR1, vcpu->arch.shadow_dbg_reg.dbcr1);
+ mtspr(SPRN_DBCR2, vcpu->arch.shadow_dbg_reg.dbcr2);
+#ifdef CONFIG_KVM_E500MC
+ mtspr(SPRN_DBCR4, vcpu->arch.shadow_dbg_reg.dbcr4);
+#endif
+ mtspr(SPRN_IAC1, vcpu->arch.shadow_dbg_reg.iac[0]);
+ mtspr(SPRN_IAC2, vcpu->arch.shadow_dbg_reg.iac[1]);
+#if CONFIG_PPC_ADV_DEBUG_IACS > 2
+ mtspr(SPRN_IAC3, vcpu->arch.shadow_dbg_reg.iac[2]);
+ mtspr(SPRN_IAC4, vcpu->arch.shadow_dbg_reg.iac[3]);
+#endif
+ mtspr(SPRN_DAC1, vcpu->arch.shadow_dbg_reg.dac[0]);
+ mtspr(SPRN_DAC2, vcpu->arch.shadow_dbg_reg.dac[1]);
+
+ /* Enable debug events after other debug registers restored */
+ mtspr(SPRN_DBCR0, vcpu->arch.shadow_dbg_reg.dbcr0);
+}
+
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+ struct kvm_guest_debug *dbg)
+{
+ struct kvmppc_booke_debug_reg *dbg_reg;
+ int n, b = 0, w = 0;
+ const u32 bp_code[] = {
+ DBCR0_IAC1 | DBCR0_IDM,
+ DBCR0_IAC2 | DBCR0_IDM,
+ DBCR0_IAC3 | DBCR0_IDM,
+ DBCR0_IAC4 | DBCR0_IDM
+ };
+ const u32 wp_code[] = {
+ DBCR0_DAC1W | DBCR0_IDM,
+ DBCR0_DAC2W | DBCR0_IDM,
+ DBCR0_DAC1R | DBCR0_IDM,
+ DBCR0_DAC2R | DBCR0_IDM
+ };
+
+ if (!(dbg->control & KVM_GUESTDBG_ENABLE)) {
+ /* Clear All debug events */
+ vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
+ vcpu->guest_debug = 0;
+ return 0;
+ }
+
+ vcpu->guest_debug = dbg->control;
+ vcpu->arch.shadow_dbg_reg.dbcr0 = 0;
+ /* Set DBCR0_EDM in guest visible DBCR0 register. */
+ vcpu->arch.dbg_reg.dbcr0 = DBCR0_EDM;
+
+ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
+ vcpu->arch.shadow_dbg_reg.dbcr0 |= DBCR0_IDM | DBCR0_IC;
+
+ if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
+ /* Code below handles only HW breakpoints */
+ kvmppc_booke_vcpu_load_debug_regs(vcpu);
+ return 0;
+ }
+
+ dbg_reg = &(vcpu->arch.shadow_dbg_reg);
+
+ /*
+ * On BOOKE (e500v2); Set DBCR1 and DBCR2 to allow debug events
+ * to occur when MSR.PR is set.
+ * On BOOKE-HV (e500mc+); MSR.PR = 0 when guest is running. So we
+ * should clear DBCR1 and DBCR2.
+ */
+#ifdef CONFIG_KVM_BOOKE_HV
+ dbg_reg->dbcr1 = 0;
+ dbg_reg->dbcr2 = 0;
+#else
+ dbg_reg->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US | DBCR1_IAC3US |
+ DBCR1_IAC4US;
+ dbg_reg->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
+#endif
+
+ for (n = 0; n < (KVMPPC_BOOKE_IAC_NUM + KVMPPC_BOOKE_DAC_NUM); n++) {
+ u32 type = dbg->arch.bp[n].type;
+
+ if (!type)
+ break;
+
+ if (type & (KVMPPC_DEBUG_WATCH_READ |
+ KVMPPC_DEBUG_WATCH_WRITE)) {
+ if (w >= KVMPPC_BOOKE_DAC_NUM)
+ continue;
+
+ if (type & KVMPPC_DEBUG_WATCH_READ)
+ dbg_reg->dbcr0 |= wp_code[w + 2];
+ if (type & KVMPPC_DEBUG_WATCH_WRITE)
+ dbg_reg->dbcr0 |= wp_code[w];
+
+ dbg_reg->dac[w] = dbg->arch.bp[n].addr;
+ w++;
+ } else if (type & KVMPPC_DEBUG_BREAKPOINT) {
+ if (b >= KVMPPC_BOOKE_IAC_NUM)
+ continue;
+
+ dbg_reg->dbcr0 |= bp_code[b];
+ dbg_reg->iac[b] = dbg->arch.bp[n].addr;
+ b++;
+ }
+ }
+
+ kvmppc_booke_vcpu_load_debug_regs(vcpu);
+ return 0;
+}
+
void kvmppc_booke_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
vcpu->cpu = smp_processor_id();
current->thread.kvm_vcpu = vcpu;
+
+ kvmppc_booke_vcpu_load_debug_regs(vcpu);
}
void kvmppc_booke_vcpu_put(struct kvm_vcpu *vcpu)
{
current->thread.kvm_vcpu = NULL;
vcpu->cpu = -1;
+
+ kvmppc_booke_vcpu_put_debug_regs(vcpu);
}
int __init kvmppc_booke_init(void)
diff --git a/arch/powerpc/kvm/e500_emulate.c b/arch/powerpc/kvm/e500_emulate.c
index e78f353..cefdd38 100644
--- a/arch/powerpc/kvm/e500_emulate.c
+++ b/arch/powerpc/kvm/e500_emulate.c
@@ -26,6 +26,7 @@
#define XOP_TLBRE 946
#define XOP_TLBWE 978
#define XOP_TLBILX 18
+#define XOP_EHPRIV 270
#ifdef CONFIG_KVM_E500MC
static int dbell2prio(ulong param)
@@ -130,6 +131,15 @@ int kvmppc_core_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
emulated = kvmppc_e500_emul_tlbivax(vcpu, ea);
break;
+ case XOP_EHPRIV:
+ run->exit_reason = KVM_EXIT_DEBUG;
+ run->debug.arch.address = vcpu->arch.pc;
+ run->debug.arch.status = 0;
+ kvmppc_account_exit(vcpu, DEBUG_EXITS);
+ emulated = EMULATE_EXIT_USER;
+ *advance = 0;
+ break;
+
default:
emulated = EMULATE_FAIL;
}
--
1.7.0.4
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