On 30/3/22 23:04, Daniel Henrique Barboza wrote:
Valgrind isn't convinced that we are initializing the values we assign
to env->spr[spr] because it doesn't understand that the 'reg_val' union
is being written by the kvm_vcpu_ioctl() that follows (via struct
kvm_one_reg).
This results in Valgrind complaining about uninitialized values every
time we use env->spr in a conditional, like this instance:
==707578== Thread 1:
==707578== Conditional jump or move depends on uninitialised value(s)
==707578== at 0xA10A40: hreg_compute_hflags_value (helper_regs.c:106)
==707578== by 0xA10C9F: hreg_compute_hflags (helper_regs.c:173)
==707578== by 0xA110F7: hreg_store_msr (helper_regs.c:262)
==707578== by 0xA051A3: ppc_cpu_reset (cpu_init.c:7168)
==707578== by 0xD4730F: device_transitional_reset (qdev.c:799)
==707578== by 0xD4A11B: resettable_phase_hold (resettable.c:182)
==707578== by 0xD49A77: resettable_assert_reset (resettable.c:60)
==707578== by 0xD4994B: resettable_reset (resettable.c:45)
==707578== by 0xD458BB: device_cold_reset (qdev.c:296)
==707578== by 0x48FBC7: cpu_reset (cpu-common.c:114)
==707578== by 0x97B5EB: spapr_reset_vcpu (spapr_cpu_core.c:38)
==707578== by 0x97BABB: spapr_cpu_core_reset (spapr_cpu_core.c:209)
==707578== Uninitialised value was created by a stack allocation
==707578== at 0xB11F08: kvm_get_one_spr (kvm.c:543)
Initializing 'reg_val' has no impact in the logic and makes Valgrind
output more bearable.
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
target/ppc/kvm.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
index dc93b99189..ce1b926e8c 100644
--- a/target/ppc/kvm.c
+++ b/target/ppc/kvm.c
@@ -543,10 +543,12 @@ static void kvm_get_one_spr(CPUState *cs, uint64_t id,
int spr)
{
PowerPCCPU *cpu = POWERPC_CPU(cs);
CPUPPCState *env = &cpu->env;
- union {
+ union reg_val {
uint32_t u32;
uint64_t u64;
- } val;
+ };
+ /* Init reg_val to avoid "uninitialised value" Valgrind warnings */
+ union reg_val val = {0};
This should also work:
-- >8 --
@@ -546,7 +546,7 @@ static void kvm_get_one_spr(CPUState *cs, uint64_t id, int
spr)
union {
uint32_t u32;
uint64_t u64;
- } val;
+ } val = { 0 };