* [PATCH 1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb()
@ 2022-01-21 16:08 Daniel Henrique Barboza
2022-01-21 18:32 ` Fabiano Rosas
2022-01-25 9:12 ` Greg Kurz
0 siblings, 2 replies; 3+ messages in thread
From: Daniel Henrique Barboza @ 2022-01-21 16:08 UTC (permalink / raw)
To: qemu-devel; +Cc: Greg Kurz, Daniel Henrique Barboza, qemu-ppc, clg, david
cpu_interrupt_exittb() was introduced by commit 044897ef4a22
("target/ppc: Fix system lockups caused by interrupt_request state
corruption") as a way to wrap cpu_interrupt() helper in BQL.
After that, commit 6d38666a8931 ("ppc: Ignore the CPU_INTERRUPT_EXITTB
interrupt with KVM") added a condition to skip this interrupt if we're
running with KVM.
Problem is that the change made by the above commit, testing for
!kvm_enabled() at the start of cpu_interrupt_exittb():
static inline void cpu_interrupt_exittb(CPUState *cs)
{
if (!kvm_enabled()) {
return;
}
(... do cpu_interrupt(cs, CPU_INTERRUPT_EXITTB) ...)
is doing the opposite of what it intended to do. This will return
immediately if not kvm_enabled(), i.e. it's a emulated CPU, and if
kvm_enabled() it will proceed to fire CPU_INTERRUPT_EXITTB.
Fix the 'skip KVM' condition so the function is a no-op when
kvm_enabled().
CC: Greg Kurz <groug@kaod.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/809
Fixes: 6d38666a8931 ("ppc: Ignore the CPU_INTERRUPT_EXITTB interrupt with KVM")
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
target/ppc/helper_regs.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
index 8671b7bb69..7dca585ddd 100644
--- a/target/ppc/helper_regs.c
+++ b/target/ppc/helper_regs.c
@@ -201,7 +201,11 @@ void cpu_get_tb_cpu_state(CPUPPCState *env, target_ulong *pc,
void cpu_interrupt_exittb(CPUState *cs)
{
- if (!kvm_enabled()) {
+ /*
+ * We don't need to worry about translation blocks
+ * when running with KVM.
+ */
+ if (kvm_enabled()) {
return;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb()
2022-01-21 16:08 [PATCH 1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb() Daniel Henrique Barboza
@ 2022-01-21 18:32 ` Fabiano Rosas
2022-01-25 9:12 ` Greg Kurz
1 sibling, 0 replies; 3+ messages in thread
From: Fabiano Rosas @ 2022-01-21 18:32 UTC (permalink / raw)
To: Daniel Henrique Barboza, qemu-devel
Cc: Daniel Henrique Barboza, qemu-ppc, Greg Kurz, david, clg
Daniel Henrique Barboza <danielhb413@gmail.com> writes:
> cpu_interrupt_exittb() was introduced by commit 044897ef4a22
> ("target/ppc: Fix system lockups caused by interrupt_request state
> corruption") as a way to wrap cpu_interrupt() helper in BQL.
>
> After that, commit 6d38666a8931 ("ppc: Ignore the CPU_INTERRUPT_EXITTB
> interrupt with KVM") added a condition to skip this interrupt if we're
> running with KVM.
>
> Problem is that the change made by the above commit, testing for
> !kvm_enabled() at the start of cpu_interrupt_exittb():
>
> static inline void cpu_interrupt_exittb(CPUState *cs)
> {
> if (!kvm_enabled()) {
> return;
> }
> (... do cpu_interrupt(cs, CPU_INTERRUPT_EXITTB) ...)
>
> is doing the opposite of what it intended to do. This will return
> immediately if not kvm_enabled(), i.e. it's a emulated CPU, and if
> kvm_enabled() it will proceed to fire CPU_INTERRUPT_EXITTB.
>
> Fix the 'skip KVM' condition so the function is a no-op when
> kvm_enabled().
>
> CC: Greg Kurz <groug@kaod.org>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/809
> Fixes: 6d38666a8931 ("ppc: Ignore the CPU_INTERRUPT_EXITTB interrupt with KVM")
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb()
2022-01-21 16:08 [PATCH 1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb() Daniel Henrique Barboza
2022-01-21 18:32 ` Fabiano Rosas
@ 2022-01-25 9:12 ` Greg Kurz
1 sibling, 0 replies; 3+ messages in thread
From: Greg Kurz @ 2022-01-25 9:12 UTC (permalink / raw)
To: Daniel Henrique Barboza; +Cc: clg, qemu-ppc, qemu-devel, david
On Fri, 21 Jan 2022 13:08:41 -0300
Daniel Henrique Barboza <danielhb413@gmail.com> wrote:
> cpu_interrupt_exittb() was introduced by commit 044897ef4a22
> ("target/ppc: Fix system lockups caused by interrupt_request state
> corruption") as a way to wrap cpu_interrupt() helper in BQL.
>
> After that, commit 6d38666a8931 ("ppc: Ignore the CPU_INTERRUPT_EXITTB
> interrupt with KVM") added a condition to skip this interrupt if we're
> running with KVM.
>
> Problem is that the change made by the above commit, testing for
> !kvm_enabled() at the start of cpu_interrupt_exittb():
>
> static inline void cpu_interrupt_exittb(CPUState *cs)
> {
> if (!kvm_enabled()) {
> return;
> }
> (... do cpu_interrupt(cs, CPU_INTERRUPT_EXITTB) ...)
>
> is doing the opposite of what it intended to do. This will return
> immediately if not kvm_enabled(), i.e. it's a emulated CPU, and if
> kvm_enabled() it will proceed to fire CPU_INTERRUPT_EXITTB.
>
Ohh boy... this is embarrassing :-\
> Fix the 'skip KVM' condition so the function is a no-op when
> kvm_enabled().
>
> CC: Greg Kurz <groug@kaod.org>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/809
> Fixes: 6d38666a8931 ("ppc: Ignore the CPU_INTERRUPT_EXITTB interrupt with KVM")
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
Reviewed-by: Greg Kurz <groug@kaod.org>
> target/ppc/helper_regs.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/target/ppc/helper_regs.c b/target/ppc/helper_regs.c
> index 8671b7bb69..7dca585ddd 100644
> --- a/target/ppc/helper_regs.c
> +++ b/target/ppc/helper_regs.c
> @@ -201,7 +201,11 @@ void cpu_get_tb_cpu_state(CPUPPCState *env, target_ulong *pc,
>
> void cpu_interrupt_exittb(CPUState *cs)
> {
> - if (!kvm_enabled()) {
> + /*
> + * We don't need to worry about translation blocks
> + * when running with KVM.
> + */
> + if (kvm_enabled()) {
> return;
> }
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-01-25 9:14 UTC | newest]
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2022-01-21 16:08 [PATCH 1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb() Daniel Henrique Barboza
2022-01-21 18:32 ` Fabiano Rosas
2022-01-25 9:12 ` Greg Kurz
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