| Message ID | 20170629010300.2848-7-f4bug@amsat.org |
|---|---|
| State | New |
| Headers | show |
Hi Peter, I think this patch belongs to 2.10, as there is no time to fix TCI + MTTCG. Should I RESEND it alone with "for 2.10" subject? One other option might be disable TCI if MTTCG enabled, but there is no ./configure option for MTTCG while there is for TCI. Regards, Phil. On 06/28/2017 10:02 PM, Philippe Mathieu-Daudé wrote: > TCI + MTTCG cause strange errors... > > $ arm-softmmu/qemu-system-arm -machine raspi2 -cpu cortex-a7 -smp 4 -accel tcg,thread=multi -kernel kernel7.img > qemu-system-arm: Guest expects a stronger memory ordering than the host provides > This may cause strange/hard to debug errors > Segmentation fault (core dumped) > > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > configure | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/configure b/configure > index c571ad14e5..510f443e06 100755 > --- a/configure > +++ b/configure > @@ -6225,7 +6225,11 @@ fi > if test "$target_softmmu" = "yes" ; then > echo "CONFIG_SOFTMMU=y" >> $config_target_mak > if test "$mttcg" = "yes" ; then > - echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak > + if test "$tcg_interpreter" = "yes" ; then > + echo "TCI enabled, disabling MTTCG" > + else > + echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak > + fi > fi > fi > if test "$target_user_only" = "yes" ; then >
Philippe Mathieu-Daudé <f4bug@amsat.org> writes: > Hi Peter, > > I think this patch belongs to 2.10, as there is no time to fix TCI + > MTTCG. Should I RESEND it alone with "for 2.10" subject? > > One other option might be disable TCI if MTTCG enabled, but there is > no ./configure option for MTTCG while there is for TCI. > > Regards, > > Phil. > > On 06/28/2017 10:02 PM, Philippe Mathieu-Daudé wrote: >> TCI + MTTCG cause strange errors... >> >> $ arm-softmmu/qemu-system-arm -machine raspi2 -cpu cortex-a7 -smp 4 -accel tcg,thread=multi -kernel kernel7.img >> qemu-system-arm: Guest expects a stronger memory ordering than the host provides >> This may cause strange/hard to debug errors >> Segmentation fault (core dumped) So this isn't TCI enabling MTTCG by accident - this is the user forcing it when it wouldn't otherwise be enabled. Hence the scary warning... >> >> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> >> --- >> configure | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/configure b/configure >> index c571ad14e5..510f443e06 100755 >> --- a/configure >> +++ b/configure >> @@ -6225,7 +6225,11 @@ fi >> if test "$target_softmmu" = "yes" ; then >> echo "CONFIG_SOFTMMU=y" >> $config_target_mak >> if test "$mttcg" = "yes" ; then >> - echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak >> + if test "$tcg_interpreter" = "yes" ; then >> + echo "TCI enabled, disabling MTTCG" >> + else >> + echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak >> + fi >> fi >> fi >> if test "$target_user_only" = "yes" ; then >> -- Alex Bennée
On 07/26/2017 05:02 AM, Alex Bennée wrote: > > Philippe Mathieu-Daudé <f4bug@amsat.org> writes: > >> Hi Peter, >> >> I think this patch belongs to 2.10, as there is no time to fix TCI + >> MTTCG. Should I RESEND it alone with "for 2.10" subject? >> >> One other option might be disable TCI if MTTCG enabled, but there is >> no ./configure option for MTTCG while there is for TCI. >> >> Regards, >> >> Phil. >> >> On 06/28/2017 10:02 PM, Philippe Mathieu-Daudé wrote: >>> TCI + MTTCG cause strange errors... >>> >>> $ arm-softmmu/qemu-system-arm -machine raspi2 -cpu cortex-a7 -smp 4 -accel tcg,thread=multi -kernel kernel7.img >>> qemu-system-arm: Guest expects a stronger memory ordering than the host provides >>> This may cause strange/hard to debug errors >>> Segmentation fault (core dumped) > > So this isn't TCI enabling MTTCG by accident - this is the user forcing > it when it wouldn't otherwise be enabled. Hence the scary warning... Hmmm this is the user enabling TCI, I'm not sure about "forcing it". Now MTTCG is enforced by the ./configure and there is no option to disable it. I posted this patch after realizing there are more TCI users/testers than just Stefan Weil, Jaroslaw Pelczar and me. Peter commented about http://qira.me/ which doesn't look very active. (see this thread: http://lists.nongnu.org/archive/html/qemu-devel/2017-06/threads.html#06528 ) Thinking about eventual downstream project using the TCI part of QEMU and trying to stay up-to-date with upstream, this patch might save headaches. Since there is no formal yes/no to this patch I'm still wondering if I should track it or no. Regards, Phil. >>> >>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> >>> --- >>> configure | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/configure b/configure >>> index c571ad14e5..510f443e06 100755 >>> --- a/configure >>> +++ b/configure >>> @@ -6225,7 +6225,11 @@ fi >>> if test "$target_softmmu" = "yes" ; then >>> echo "CONFIG_SOFTMMU=y" >> $config_target_mak >>> if test "$mttcg" = "yes" ; then >>> - echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak >>> + if test "$tcg_interpreter" = "yes" ; then >>> + echo "TCI enabled, disabling MTTCG" >>> + else >>> + echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak >>> + fi >>> fi >>> fi >>> if test "$target_user_only" = "yes" ; then >>> > > > -- > Alex Bennée >
On 08/03/2017 10:40 AM, Philippe Mathieu-Daudé wrote: > On 07/26/2017 05:02 AM, Alex Bennée wrote: >> >> Philippe Mathieu-Daudé <f4bug@amsat.org> writes: >> >>> Hi Peter, >>> >>> I think this patch belongs to 2.10, as there is no time to fix TCI + >>> MTTCG. Should I RESEND it alone with "for 2.10" subject? >>> >>> One other option might be disable TCI if MTTCG enabled, but there is >>> no ./configure option for MTTCG while there is for TCI. >>> >>> Regards, >>> >>> Phil. >>> >>> On 06/28/2017 10:02 PM, Philippe Mathieu-Daudé wrote: >>>> TCI + MTTCG cause strange errors... >>>> >>>> $ arm-softmmu/qemu-system-arm -machine raspi2 -cpu cortex-a7 -smp 4 >>>> -accel tcg,thread=multi -kernel kernel7.img >>>> qemu-system-arm: Guest expects a stronger memory ordering than the host >>>> provides >>>> This may cause strange/hard to debug errors >>>> Segmentation fault (core dumped) >> >> So this isn't TCI enabling MTTCG by accident - this is the user forcing >> it when it wouldn't otherwise be enabled. Hence the scary warning... > > Hmmm this is the user enabling TCI, I'm not sure about "forcing it". > Now MTTCG is enforced by the ./configure and there is no option to disable it. Er, no. If you write "-accel tcg" you are not forcing mttcg on. If you write "-accel tcg,thread=multi" you are forcing it on. If you write "-accel tcg,thread=single" you are forcing it off. MTTCG is only enabled by default if TCG_TARGET_DEFAULT_MO is defined, and in the case of TCI, it is not. r~
On 08/03/2017 02:56 PM, Richard Henderson wrote: > On 08/03/2017 10:40 AM, Philippe Mathieu-Daudé wrote: >> On 07/26/2017 05:02 AM, Alex Bennée wrote: >>> >>> Philippe Mathieu-Daudé <f4bug@amsat.org> writes: >>> >>>> Hi Peter, >>>> >>>> I think this patch belongs to 2.10, as there is no time to fix TCI + >>>> MTTCG. Should I RESEND it alone with "for 2.10" subject? >>>> >>>> One other option might be disable TCI if MTTCG enabled, but there is >>>> no ./configure option for MTTCG while there is for TCI. >>>> >>>> Regards, >>>> >>>> Phil. >>>> >>>> On 06/28/2017 10:02 PM, Philippe Mathieu-Daudé wrote: >>>>> TCI + MTTCG cause strange errors... >>>>> >>>>> $ arm-softmmu/qemu-system-arm -machine raspi2 -cpu cortex-a7 -smp 4 >>>>> -accel tcg,thread=multi -kernel kernel7.img >>>>> qemu-system-arm: Guest expects a stronger memory ordering than the host >>>>> provides >>>>> This may cause strange/hard to debug errors >>>>> Segmentation fault (core dumped) >>> >>> So this isn't TCI enabling MTTCG by accident - this is the user forcing >>> it when it wouldn't otherwise be enabled. Hence the scary warning... >> >> Hmmm this is the user enabling TCI, I'm not sure about "forcing it". >> Now MTTCG is enforced by the ./configure and there is no option to disable it. > > Er, no. > > If you write "-accel tcg" you are not forcing mttcg on. > If you write "-accel tcg,thread=multi" you are forcing it on. Ok! I obviously missed this part. > If you write "-accel tcg,thread=single" you are forcing it off. > > MTTCG is only enabled by default if TCG_TARGET_DEFAULT_MO is defined, and in > the case of TCI, it is not. Ok, so I misunderstood Alex :) I thought about ./configure enabled while he was describing -accel enabled. Thanks for pointing that out :) > > > r~ >
diff --git a/configure b/configure index c571ad14e5..510f443e06 100755 --- a/configure +++ b/configure @@ -6225,7 +6225,11 @@ fi if test "$target_softmmu" = "yes" ; then echo "CONFIG_SOFTMMU=y" >> $config_target_mak if test "$mttcg" = "yes" ; then - echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak + if test "$tcg_interpreter" = "yes" ; then + echo "TCI enabled, disabling MTTCG" + else + echo "TARGET_SUPPORTS_MTTCG=y" >> $config_target_mak + fi fi fi if test "$target_user_only" = "yes" ; then
TCI + MTTCG cause strange errors... $ arm-softmmu/qemu-system-arm -machine raspi2 -cpu cortex-a7 -smp 4 -accel tcg,thread=multi -kernel kernel7.img qemu-system-arm: Guest expects a stronger memory ordering than the host provides This may cause strange/hard to debug errors Segmentation fault (core dumped) Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- configure | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)