| Message ID | 1458141183-27207-4-git-send-email-lvivier@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 16.03.2016 16:13, Laurent Vivier wrote: > Check in MSR if the SF bit is set (64bit mode is enabled) > > Signed-off-by: Laurent Vivier <lvivier@redhat.com> > --- > powerpc/emulator.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/powerpc/emulator.c b/powerpc/emulator.c > index 1215c4f..b66c1d7 100644 > --- a/powerpc/emulator.c > +++ b/powerpc/emulator.c > @@ -32,12 +32,26 @@ static void test_illegal(void) > report_prefix_pop(); > } > > +static void test_64bit(void) > +{ > + uint64_t msr; > + > + report_prefix_push("64bit"); > + > + asm("mfmsr %[msr]": [msr] "=r" (msr)); > + > + report("detected", msr & 0x8000000000000000UL); > + > + report_prefix_pop(); > +} > + > int main(void) > { > handle_exception(0x700, program_check_handler, (void *)&is_invalid); > > report_prefix_push("emulator"); > > + test_64bit(); > test_illegal(); > > report_prefix_pop(); Reviewed-by: Thomas Huth <thuth@redhat.com> But I still wonder how kvm-unit-tests worked at all before the 64-bit mode has been fixed in QEMU ... I mean kvm-unit-tests is compiled with 64-bit code, but it's still working when run in 32-bit? Something really strange was going on here... Thomas -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Mar 18, 2016 at 09:28:33AM +0100, Thomas Huth wrote: > On 16.03.2016 16:13, Laurent Vivier wrote: > > Check in MSR if the SF bit is set (64bit mode is enabled) > > > > Signed-off-by: Laurent Vivier <lvivier@redhat.com> > > --- > > powerpc/emulator.c | 14 ++++++++++++++f958ee745f70 > > 1 file changed, 14 insertions(+) > > > > diff --git a/powerpc/emulator.c b/powerpc/emulator.c > > index 1215c4f..b66c1d7 100644 > > --- a/powerpc/emulator.c > > +++ b/powerpc/emulator.c > > @@ -32,12 +32,26 @@ static void test_illegal(void) > > report_prefix_pop(); > > } > > > > +static void test_64bit(void) > > +{ > > + uint64_t msr; > > + > > + report_prefix_push("64bit"); > > + > > + asm("mfmsr %[msr]": [msr] "=r" (msr)); > > + > > + report("detected", msr & 0x8000000000000000UL); > > + > > + report_prefix_pop(); > > +} > > + > > int main(void) > > { > > handle_exception(0x700, program_check_handler, (void *)&is_invalid); > > > > report_prefix_push("emulator"); > > > > + test_64bit(); > > test_illegal(); > > > > report_prefix_pop(); > > Reviewed-by: Thomas Huth <thuth@redhat.com> > > But I still wonder how kvm-unit-tests worked at all before the 64-bit > mode has been fixed in QEMU ... I mean kvm-unit-tests is compiled with > 64-bit code, but it's still working when run in 32-bit? Something really > strange was going on here... On Power processors, there's not as much difference between 32-bit and 64-bit mode as you might expect. In 32-bit mode on a 64-bit processor, you can use all 64 bits of the registers and execute 64-bit instructions. The only things that change in 32-bit mode are that (a) effective addresses are truncated to 32 bits and (b) dot-form instructions (e.g. "add.") set CR0 based on the 32-bit result rather than the 64-bit result. Paul. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 18.03.2016 09:38, Paul Mackerras wrote: > On Fri, Mar 18, 2016 at 09:28:33AM +0100, Thomas Huth wrote: >> On 16.03.2016 16:13, Laurent Vivier wrote: >>> Check in MSR if the SF bit is set (64bit mode is enabled) >>> >>> Signed-off-by: Laurent Vivier <lvivier@redhat.com> >>> --- >>> powerpc/emulator.c | 14 ++++++++++++++f958ee745f70 >>> 1 file changed, 14 insertions(+) >>> >>> diff --git a/powerpc/emulator.c b/powerpc/emulator.c >>> index 1215c4f..b66c1d7 100644 >>> --- a/powerpc/emulator.c >>> +++ b/powerpc/emulator.c >>> @@ -32,12 +32,26 @@ static void test_illegal(void) >>> report_prefix_pop(); >>> } >>> >>> +static void test_64bit(void) >>> +{ >>> + uint64_t msr; >>> + >>> + report_prefix_push("64bit"); >>> + >>> + asm("mfmsr %[msr]": [msr] "=r" (msr)); >>> + >>> + report("detected", msr & 0x8000000000000000UL); >>> + >>> + report_prefix_pop(); >>> +} >>> + >>> int main(void) >>> { >>> handle_exception(0x700, program_check_handler, (void *)&is_invalid); >>> >>> report_prefix_push("emulator"); >>> >>> + test_64bit(); >>> test_illegal(); >>> >>> report_prefix_pop(); >> >> Reviewed-by: Thomas Huth <thuth@redhat.com> >> >> But I still wonder how kvm-unit-tests worked at all before the 64-bit >> mode has been fixed in QEMU ... I mean kvm-unit-tests is compiled with >> 64-bit code, but it's still working when run in 32-bit? Something really >> strange was going on here... > > On Power processors, there's not as much difference between 32-bit and > 64-bit mode as you might expect. In 32-bit mode on a 64-bit > processor, you can use all 64 bits of the registers and execute 64-bit > instructions. The only things that change in 32-bit mode are that (a) > effective addresses are truncated to 32 bits and (b) dot-form > instructions (e.g. "add.") set CR0 based on the 32-bit result rather > than the 64-bit result. Ah, ok, ... and since kvm-unit-tests normally does not use the RAM > 4 GB, we didn't notice the truncation. Makes sense. Thanks for the clarification! Thomas -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/powerpc/emulator.c b/powerpc/emulator.c index 1215c4f..b66c1d7 100644 --- a/powerpc/emulator.c +++ b/powerpc/emulator.c @@ -32,12 +32,26 @@ static void test_illegal(void) report_prefix_pop(); } +static void test_64bit(void) +{ + uint64_t msr; + + report_prefix_push("64bit"); + + asm("mfmsr %[msr]": [msr] "=r" (msr)); + + report("detected", msr & 0x8000000000000000UL); + + report_prefix_pop(); +} + int main(void) { handle_exception(0x700, program_check_handler, (void *)&is_invalid); report_prefix_push("emulator"); + test_64bit(); test_illegal(); report_prefix_pop();
Check in MSR if the SF bit is set (64bit mode is enabled) Signed-off-by: Laurent Vivier <lvivier@redhat.com> --- powerpc/emulator.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)