| Message ID | 20230110185823.1856951-2-mizhang@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/4] KVM: selftests: x86: Fix an error in comment of amx_test | expand |
On Tue, Jan 10, 2023, Mingwei Zhang wrote: > After the execution of __tilerelease(), AMX component will be in INIT > state. Therefore, execution of xsavec saving the AMX state into memory will s/xsavec/XSAVEC > cause the XSTATE_BV[18] cleared in xheader. However, the XCOMP_BV[18] will > remain set. Fix the error in comment. > > Cc: Jim Mattson <jmattson@google.com> > Cc: Venkatesh Srinivas <venkateshs@google.com> > Cc: Aaron Lewis <aaronlewis@google.com> > No need for a blank line. > Signed-off-by: Mingwei Zhang <mizhang@google.com> > --- > tools/testing/selftests/kvm/x86_64/amx_test.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c > index bd72c6eb3b67..16533949a189 100644 > --- a/tools/testing/selftests/kvm/x86_64/amx_test.c > +++ b/tools/testing/selftests/kvm/x86_64/amx_test.c > @@ -204,7 +204,7 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg, > GUEST_SYNC(4); > __tilerelease(); > GUEST_SYNC(5); > - /* bit 18 not in the XCOMP_BV after xsavec() */ > + /* bit 18 not in the XSTATE_BV after xsavec() */ I would rather overhaul the entire comment, e.g. /* Verify XTILEDATA is not set in XSTATE_BV after XSAVEC */ I had to look at the definition of XFEATURE_XTILEDATA to verify that yes, indeed, bit 18 is XTILEDATA. As for xsavec() vs. XSAVE, IIUC the clearing of XCOMP_BV[18] is a side effect of XSAVEC the instruction, not something extra done by xsavec() the function. > set_xstatebv(xsave_data, XFEATURE_MASK_XTILEDATA); > __xsavec(xsave_data, XFEATURE_MASK_XTILEDATA); > GUEST_ASSERT((get_xstatebv(xsave_data) & XFEATURE_MASK_XTILEDATA) == 0); > -- > 2.39.0.314.g84b9a713c41-goog >
On Tue, Feb 7, 2023 at 5:13 PM Sean Christopherson <seanjc@google.com> wrote: > > On Tue, Jan 10, 2023, Mingwei Zhang wrote: > > After the execution of __tilerelease(), AMX component will be in INIT > > state. Therefore, execution of xsavec saving the AMX state into memory will > > s/xsavec/XSAVEC > > > cause the XSTATE_BV[18] cleared in xheader. However, the XCOMP_BV[18] will > > remain set. Fix the error in comment. > > > > Cc: Jim Mattson <jmattson@google.com> > > Cc: Venkatesh Srinivas <venkateshs@google.com> > > Cc: Aaron Lewis <aaronlewis@google.com> > > > > No need for a blank line. ack. > > > Signed-off-by: Mingwei Zhang <mizhang@google.com> > > --- > > tools/testing/selftests/kvm/x86_64/amx_test.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c > > index bd72c6eb3b67..16533949a189 100644 > > --- a/tools/testing/selftests/kvm/x86_64/amx_test.c > > +++ b/tools/testing/selftests/kvm/x86_64/amx_test.c > > @@ -204,7 +204,7 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg, > > GUEST_SYNC(4); > > __tilerelease(); > > GUEST_SYNC(5); > > - /* bit 18 not in the XCOMP_BV after xsavec() */ > > + /* bit 18 not in the XSTATE_BV after xsavec() */ > > I would rather overhaul the entire comment, e.g. > > /* Verify XTILEDATA is not set in XSTATE_BV after XSAVEC */ > > I had to look at the definition of XFEATURE_XTILEDATA to verify that yes, indeed, > bit 18 is XTILEDATA. > > As for xsavec() vs. XSAVE, IIUC the clearing of XCOMP_BV[18] is a side effect of > XSAVEC the instruction, not something extra done by xsavec() the function. I see, that's why you asked me to use capital words. > > > set_xstatebv(xsave_data, XFEATURE_MASK_XTILEDATA); > > __xsavec(xsave_data, XFEATURE_MASK_XTILEDATA); > > GUEST_ASSERT((get_xstatebv(xsave_data) & XFEATURE_MASK_XTILEDATA) == 0); > > -- > > 2.39.0.314.g84b9a713c41-goog > >
diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c index bd72c6eb3b67..16533949a189 100644 --- a/tools/testing/selftests/kvm/x86_64/amx_test.c +++ b/tools/testing/selftests/kvm/x86_64/amx_test.c @@ -204,7 +204,7 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg, GUEST_SYNC(4); __tilerelease(); GUEST_SYNC(5); - /* bit 18 not in the XCOMP_BV after xsavec() */ + /* bit 18 not in the XSTATE_BV after xsavec() */ set_xstatebv(xsave_data, XFEATURE_MASK_XTILEDATA); __xsavec(xsave_data, XFEATURE_MASK_XTILEDATA); GUEST_ASSERT((get_xstatebv(xsave_data) & XFEATURE_MASK_XTILEDATA) == 0);
After the execution of __tilerelease(), AMX component will be in INIT state. Therefore, execution of xsavec saving the AMX state into memory will cause the XSTATE_BV[18] cleared in xheader. However, the XCOMP_BV[18] will remain set. Fix the error in comment. Cc: Jim Mattson <jmattson@google.com> Cc: Venkatesh Srinivas <venkateshs@google.com> Cc: Aaron Lewis <aaronlewis@google.com> Signed-off-by: Mingwei Zhang <mizhang@google.com> --- tools/testing/selftests/kvm/x86_64/amx_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)