* [PATCH] target/i386: raise FERR interrupt with iothread locked
@ 2023-08-29 15:25 Paolo Bonzini
2023-08-29 15:45 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2023-08-29 15:25 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-stable
Otherwise tcg_handle_interrupt() triggers an assertion failure:
#5 0x0000555555c97369 in tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:83
#6 tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:81
#7 0x0000555555b4d58b in pic_irq_request (opaque=<optimized out>, irq=<optimized out>, level=1) at ../hw/i386/x86.c:555
#8 0x0000555555b4f218 in gsi_handler (opaque=0x5555579423d0, n=13, level=1) at ../hw/i386/x86.c:611
#9 0x00007fffa42bde14 in code_gen_buffer ()
#10 0x0000555555c724bb in cpu_tb_exec (cpu=cpu@entry=0x555557434cb0, itb=<optimized out>, tb_exit=tb_exit@entry=0x7fffe9bfd658) at ../accel/tcg/cpu-exec.c:457
Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1808
Reported-by: NyanCatTW1 <https://gitlab.com/a0939712328>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target/i386/tcg/sysemu/fpu_helper.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/target/i386/tcg/sysemu/fpu_helper.c b/target/i386/tcg/sysemu/fpu_helper.c
index 1c3610da3b9..fd8cc72a026 100644
--- a/target/i386/tcg/sysemu/fpu_helper.c
+++ b/target/i386/tcg/sysemu/fpu_helper.c
@@ -31,7 +31,9 @@ void x86_register_ferr_irq(qemu_irq irq)
void fpu_check_raise_ferr_irq(CPUX86State *env)
{
if (ferr_irq && !(env->hflags2 & HF2_IGNNE_MASK)) {
+ qemu_mutex_lock_iothread();
qemu_irq_raise(ferr_irq);
+ qemu_mutex_unlock_iothread();
return;
}
}
--
2.41.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] target/i386: raise FERR interrupt with iothread locked
2023-08-29 15:25 [PATCH] target/i386: raise FERR interrupt with iothread locked Paolo Bonzini
@ 2023-08-29 15:45 ` Philippe Mathieu-Daudé
2023-08-29 16:58 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2023-08-29 15:45 UTC (permalink / raw)
To: Paolo Bonzini, qemu-devel; +Cc: qemu-stable
On 29/8/23 17:25, Paolo Bonzini wrote:
> Otherwise tcg_handle_interrupt() triggers an assertion failure:
>
> #5 0x0000555555c97369 in tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:83
> #6 tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:81
> #7 0x0000555555b4d58b in pic_irq_request (opaque=<optimized out>, irq=<optimized out>, level=1) at ../hw/i386/x86.c:555
> #8 0x0000555555b4f218 in gsi_handler (opaque=0x5555579423d0, n=13, level=1) at ../hw/i386/x86.c:611
> #9 0x00007fffa42bde14 in code_gen_buffer ()
> #10 0x0000555555c724bb in cpu_tb_exec (cpu=cpu@entry=0x555557434cb0, itb=<optimized out>, tb_exit=tb_exit@entry=0x7fffe9bfd658) at ../accel/tcg/cpu-exec.c:457
>
> Cc: qemu-stable@nongnu.org
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1808
> Reported-by: NyanCatTW1 <https://gitlab.com/a0939712328>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> target/i386/tcg/sysemu/fpu_helper.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/target/i386/tcg/sysemu/fpu_helper.c b/target/i386/tcg/sysemu/fpu_helper.c
> index 1c3610da3b9..fd8cc72a026 100644
> --- a/target/i386/tcg/sysemu/fpu_helper.c
> +++ b/target/i386/tcg/sysemu/fpu_helper.c
> @@ -31,7 +31,9 @@ void x86_register_ferr_irq(qemu_irq irq)
> void fpu_check_raise_ferr_irq(CPUX86State *env)
> {
> if (ferr_irq && !(env->hflags2 & HF2_IGNNE_MASK)) {
> + qemu_mutex_lock_iothread();
> qemu_irq_raise(ferr_irq);
> + qemu_mutex_unlock_iothread();
> return;
> }
> }
OK, so:
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Maybe for completeness, squash this? :
-- >8 --
diff --git a/target/i386/tcg/sysemu/fpu_helper.c
b/target/i386/tcg/sysemu/fpu_helper.c
index 1c3610da3b..320bd69f43 100644
--- a/target/i386/tcg/sysemu/fpu_helper.c
+++ b/target/i386/tcg/sysemu/fpu_helper.c
@@ -45,6 +45,8 @@ void cpu_clear_ignne(void)
void cpu_set_ignne(void)
{
CPUX86State *env = &X86_CPU(first_cpu)->env;
+
+ g_assert(qemu_mutex_iothread_locked());
env->hflags2 |= HF2_IGNNE_MASK;
/*
---
Somehow similar pattern so what about MIPS MTC0?:
mtc0_compare() ->
helper_mtc0_compare() ->
cpu_mips_store_compare() ->
qemu_irq_lower()
Regards,
Phil.
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] target/i386: raise FERR interrupt with iothread locked
2023-08-29 15:45 ` Philippe Mathieu-Daudé
@ 2023-08-29 16:58 ` Paolo Bonzini
2023-08-29 17:01 ` Peter Maydell
0 siblings, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2023-08-29 16:58 UTC (permalink / raw)
To: Philippe Mathieu-Daudé; +Cc: qemu-devel, qemu-stable
On Tue, Aug 29, 2023 at 5:46 PM Philippe Mathieu-Daudé
<philmd@linaro.org> wrote:
>
> On 29/8/23 17:25, Paolo Bonzini wrote:
> > Otherwise tcg_handle_interrupt() triggers an assertion failure:
> >
> > #5 0x0000555555c97369 in tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:83
> > #6 tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:81
> > #7 0x0000555555b4d58b in pic_irq_request (opaque=<optimized out>, irq=<optimized out>, level=1) at ../hw/i386/x86.c:555
> > #8 0x0000555555b4f218 in gsi_handler (opaque=0x5555579423d0, n=13, level=1) at ../hw/i386/x86.c:611
> > #9 0x00007fffa42bde14 in code_gen_buffer ()
> > #10 0x0000555555c724bb in cpu_tb_exec (cpu=cpu@entry=0x555557434cb0, itb=<optimized out>, tb_exit=tb_exit@entry=0x7fffe9bfd658) at ../accel/tcg/cpu-exec.c:457
> >
> > Cc: qemu-stable@nongnu.org
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1808
> > Reported-by: NyanCatTW1 <https://gitlab.com/a0939712328>
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> > target/i386/tcg/sysemu/fpu_helper.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/target/i386/tcg/sysemu/fpu_helper.c b/target/i386/tcg/sysemu/fpu_helper.c
> > index 1c3610da3b9..fd8cc72a026 100644
> > --- a/target/i386/tcg/sysemu/fpu_helper.c
> > +++ b/target/i386/tcg/sysemu/fpu_helper.c
> > @@ -31,7 +31,9 @@ void x86_register_ferr_irq(qemu_irq irq)
> > void fpu_check_raise_ferr_irq(CPUX86State *env)
> > {
> > if (ferr_irq && !(env->hflags2 & HF2_IGNNE_MASK)) {
> > + qemu_mutex_lock_iothread();
> > qemu_irq_raise(ferr_irq);
> > + qemu_mutex_unlock_iothread();
> > return;
> > }
> > }
>
> OK, so:
>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Actually Richard has a better (though also slightly incomplete) patch
in the bug, so I'll send v2.
> void cpu_set_ignne(void)
> {
> CPUX86State *env = &X86_CPU(first_cpu)->env;
> +
> + g_assert(qemu_mutex_iothread_locked());
qemu_irq_lower() is fine because it doesn't result in a call to
tcg_handle_interrupt().
Paolo
> Somehow similar pattern so what about MIPS MTC0?:
>
> mtc0_compare() ->
> helper_mtc0_compare() ->
> cpu_mips_store_compare() ->
> qemu_irq_lower()
Lower is a bit safer
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] target/i386: raise FERR interrupt with iothread locked
2023-08-29 16:58 ` Paolo Bonzini
@ 2023-08-29 17:01 ` Peter Maydell
0 siblings, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2023-08-29 17:01 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: Philippe Mathieu-Daudé, qemu-devel, qemu-stable
On Tue, 29 Aug 2023 at 17:59, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On Tue, Aug 29, 2023 at 5:46 PM Philippe Mathieu-Daudé
> <philmd@linaro.org> wrote:
> >
> > On 29/8/23 17:25, Paolo Bonzini wrote:
> > > Otherwise tcg_handle_interrupt() triggers an assertion failure:
> > >
> > > #5 0x0000555555c97369 in tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:83
> > > #6 tcg_handle_interrupt (cpu=0x555557434cb0, mask=2) at ../accel/tcg/tcg-accel-ops.c:81
> > > #7 0x0000555555b4d58b in pic_irq_request (opaque=<optimized out>, irq=<optimized out>, level=1) at ../hw/i386/x86.c:555
> > > #8 0x0000555555b4f218 in gsi_handler (opaque=0x5555579423d0, n=13, level=1) at ../hw/i386/x86.c:611
> > > #9 0x00007fffa42bde14 in code_gen_buffer ()
> > > #10 0x0000555555c724bb in cpu_tb_exec (cpu=cpu@entry=0x555557434cb0, itb=<optimized out>, tb_exit=tb_exit@entry=0x7fffe9bfd658) at ../accel/tcg/cpu-exec.c:457
> > >
> > > Cc: qemu-stable@nongnu.org
> > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1808
> > > Reported-by: NyanCatTW1 <https://gitlab.com/a0939712328>
> > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > > ---
> > > target/i386/tcg/sysemu/fpu_helper.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/target/i386/tcg/sysemu/fpu_helper.c b/target/i386/tcg/sysemu/fpu_helper.c
> > > index 1c3610da3b9..fd8cc72a026 100644
> > > --- a/target/i386/tcg/sysemu/fpu_helper.c
> > > +++ b/target/i386/tcg/sysemu/fpu_helper.c
> > > @@ -31,7 +31,9 @@ void x86_register_ferr_irq(qemu_irq irq)
> > > void fpu_check_raise_ferr_irq(CPUX86State *env)
> > > {
> > > if (ferr_irq && !(env->hflags2 & HF2_IGNNE_MASK)) {
> > > + qemu_mutex_lock_iothread();
> > > qemu_irq_raise(ferr_irq);
> > > + qemu_mutex_unlock_iothread();
> > > return;
> > > }
> > > }
> >
> > OK, so:
> >
> > Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>
> Actually Richard has a better (though also slightly incomplete) patch
> in the bug, so I'll send v2.
>
> > void cpu_set_ignne(void)
> > {
> > CPUX86State *env = &X86_CPU(first_cpu)->env;
> > +
> > + g_assert(qemu_mutex_iothread_locked());
>
> qemu_irq_lower() is fine because it doesn't result in a call to
> tcg_handle_interrupt().
It does potentially result in calling code in a device model
that assumes that it is protected by the iothread lock,
though...
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-08-29 15:25 [PATCH] target/i386: raise FERR interrupt with iothread locked Paolo Bonzini
2023-08-29 15:45 ` Philippe Mathieu-Daudé
2023-08-29 16:58 ` Paolo Bonzini
2023-08-29 17:01 ` Peter Maydell
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