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[PATCH v5 23/24] spapr: Fix vpa dispatch count for record-replay
From: |
Nicholas Piggin |
Subject: |
[PATCH v5 23/24] spapr: Fix vpa dispatch count for record-replay |
Date: |
Tue, 19 Mar 2024 01:46:20 +1000 |
The dispatch count is a field in guest memory that the hypervisor
increments when preempting and dispatching the guest. This was not
being done deterministically with respect to icount, because tcg
exec exit is not deterministic (e.g., an async event could cause it).
Change vpa dispatch count increment to keep track of whether the
vCPU is considered dispatched or not, and only consider it preempted
when calling cede / confer / join / stop-self / etc.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
include/hw/ppc/spapr_cpu_core.h | 3 +++
hw/ppc/spapr.c | 36 ++-------------------------------
hw/ppc/spapr_hcall.c | 33 ++++++++++++++++++++++++++++++
hw/ppc/spapr_rtas.c | 1 +
4 files changed, 39 insertions(+), 34 deletions(-)
diff --git a/include/hw/ppc/spapr_cpu_core.h b/include/hw/ppc/spapr_cpu_core.h
index 69a52e39b8..5feb0ecc2a 100644
--- a/include/hw/ppc/spapr_cpu_core.h
+++ b/include/hw/ppc/spapr_cpu_core.h
@@ -47,6 +47,7 @@ typedef struct SpaprCpuState {
uint64_t vpa_addr;
uint64_t slb_shadow_addr, slb_shadow_size;
uint64_t dtl_addr, dtl_size;
+ bool dispatched; /* for vpa dispatch counter tracking */
bool prod; /* not migrated, only used to improve dispatch latencies */
struct ICPState *icp;
struct XiveTCTX *tctx;
@@ -61,4 +62,6 @@ static inline SpaprCpuState *spapr_cpu_state(PowerPCCPU *cpu)
return (SpaprCpuState *)cpu->machine_data;
}
+void vpa_dispatch(CPUState *cs, SpaprCpuState *spapr_cpu, bool dispatch);
+
#endif
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index c417f9dd52..07b004fdec 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4599,47 +4599,15 @@ static void spapr_cpu_exec_enter(PPCVirtualHypervisor
*vhyp, PowerPCCPU *cpu)
{
SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
- /* These are only called by TCG, KVM maintains dispatch state */
-
spapr_cpu->prod = false;
- if (spapr_cpu->vpa_addr) {
+ if (!spapr_cpu->dispatched) {
CPUState *cs = CPU(cpu);
- uint32_t dispatch;
-
- dispatch = ldl_be_phys(cs->as,
- spapr_cpu->vpa_addr + VPA_DISPATCH_COUNTER);
- dispatch++;
- if ((dispatch & 1) != 0) {
- qemu_log_mask(LOG_GUEST_ERROR,
- "VPA: incorrect dispatch counter value for "
- "dispatched partition %u, correcting.\n", dispatch);
- dispatch++;
- }
- stl_be_phys(cs->as,
- spapr_cpu->vpa_addr + VPA_DISPATCH_COUNTER, dispatch);
+ vpa_dispatch(cs, spapr_cpu, true);
}
}
static void spapr_cpu_exec_exit(PPCVirtualHypervisor *vhyp, PowerPCCPU *cpu)
{
- SpaprCpuState *spapr_cpu = spapr_cpu_state(cpu);
-
- if (spapr_cpu->vpa_addr) {
- CPUState *cs = CPU(cpu);
- uint32_t dispatch;
-
- dispatch = ldl_be_phys(cs->as,
- spapr_cpu->vpa_addr + VPA_DISPATCH_COUNTER);
- dispatch++;
- if ((dispatch & 1) != 1) {
- qemu_log_mask(LOG_GUEST_ERROR,
- "VPA: incorrect dispatch counter value for "
- "preempted partition %u, correcting.\n", dispatch);
- dispatch++;
- }
- stl_be_phys(cs->as,
- spapr_cpu->vpa_addr + VPA_DISPATCH_COUNTER, dispatch);
- }
}
static void spapr_machine_class_init(ObjectClass *oc, void *data)
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index 5e1d020e3d..907e09c2c3 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -487,6 +487,36 @@ static target_ulong h_register_vpa(PowerPCCPU *cpu,
SpaprMachineState *spapr,
return ret;
}
+void vpa_dispatch(CPUState *cs, SpaprCpuState *spapr_cpu, bool dispatch)
+{
+ uint32_t counter;
+
+ if (!dispatch) {
+ assert(spapr_cpu->dispatched);
+ } else {
+ assert(!spapr_cpu->dispatched);
+ }
+ spapr_cpu->dispatched = dispatch;
+
+ return;
+
+ if (!spapr_cpu->vpa_addr) {
+ return;
+ }
+
+ /* These are only called by TCG, KVM maintains dispatch state */
+ counter = ldl_be_phys(cs->as, spapr_cpu->vpa_addr + VPA_DISPATCH_COUNTER);
+ counter++;
+ if ((counter & 1) != dispatch) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "VPA: incorrect dispatch counter value for "
+ "%s partition %u, correcting.\n",
+ dispatch ? "preempted" : "running", counter);
+ counter++;
+ }
+ stl_be_phys(cs->as, spapr_cpu->vpa_addr + VPA_DISPATCH_COUNTER, counter);
+}
+
static target_ulong h_cede(PowerPCCPU *cpu, SpaprMachineState *spapr,
target_ulong opcode, target_ulong *args)
{
@@ -505,6 +535,7 @@ static target_ulong h_cede(PowerPCCPU *cpu,
SpaprMachineState *spapr,
if (!cpu_has_work(cs)) {
cs->halted = 1;
+ vpa_dispatch(cs, spapr_cpu, false);
cs->exception_index = EXCP_HLT;
cs->exit_request = 1;
ppc_maybe_interrupt(env);
@@ -531,6 +562,8 @@ static target_ulong h_confer_self(PowerPCCPU *cpu)
cs->exit_request = 1;
ppc_maybe_interrupt(&cpu->env);
+ vpa_dispatch(cs, spapr_cpu, false);
+
return H_SUCCESS;
}
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index f329693c55..8ce4230223 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -216,6 +216,7 @@ static void rtas_stop_self(PowerPCCPU *cpu,
SpaprMachineState *spapr,
*/
env->spr[SPR_PSSCR] |= PSSCR_EC;
cs->halted = 1;
+ vpa_dispatch(cs, spapr_cpu_state(cpu), false);
ppc_store_lpcr(cpu, env->spr[SPR_LPCR] & ~pcc->lpcr_pm);
kvmppc_set_reg_ppc_online(cpu, 0);
qemu_cpu_kick(cs);
--
2.42.0
- [PATCH v5 15/24] tests/avocado: reverse_debugging.py add test for x86-64 q35 machine, (continued)
- [PATCH v5 15/24] tests/avocado: reverse_debugging.py add test for x86-64 q35 machine, Nicholas Piggin, 2024/03/18
- [PATCH v5 16/24] tests/avocado: reverse_debugging.py verify addresses between record and replay, Nicholas Piggin, 2024/03/18
- [PATCH v5 17/24] tests/avocado: reverse_debugging.py stop VM before sampling icount, Nicholas Piggin, 2024/03/18
- [PATCH v5 14/24] tests/avocado: reverse_debugging.py mark aarch64 and pseries as not flaky, Nicholas Piggin, 2024/03/18
- [PATCH v5 18/24] tests/avocado: reverse_debugging reverse-step at the end of the trace, Nicholas Piggin, 2024/03/18
- [PATCH v5 19/24] tests/avocado: reverse_debugging.py add snapshot testing, Nicholas Piggin, 2024/03/18
- [PATCH v5 20/24] replay: simple auto-snapshot mode for record, Nicholas Piggin, 2024/03/18
- [PATCH v5 21/24] tests/avocado: reverse_debugging.py test auto-snapshot mode, Nicholas Piggin, 2024/03/18
- [PATCH v5 22/24] target/ppc: fix timebase register reset state, Nicholas Piggin, 2024/03/18
- [PATCH v5 23/24] spapr: Fix vpa dispatch count for record-replay,
Nicholas Piggin <=
- [PATCH v5 24/24] tests/avocado: replay_linux.py add ppc64 pseries test, Nicholas Piggin, 2024/03/18