| Message ID | 20220121160841.9102-1-danielhb413@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/1] target/ppc: fix 'skip KVM' cond in cpu_interrupt_exittb() | expand |
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>
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; > } >
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; }
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(-)