Message ID | 75c077bc-ecf3-45fe-1a71-0804fe6aaaf4@suse.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | libx86/CPUID: fix (not just) leaf 7 processing | expand |
On 23/03/2020 12:06, Jan Beulich wrote: > For one, subleaves within the respective union shouldn't live in > separate sub-structures. Oops, and of course this stays hidden right now because there is no overlap in known bits between subleaf 0 and 1 yet. > And then x86_cpuid_policy_fill_native() should, > as it did originally, iterate over all subleaves here as well as over > all main leaves. I was clearly asleep when writing that bugfix. Again - it says hidden because our local max_leaves are lower than ~all hardware these days. > Switch to using a "<= MIN()"-based approach similar to > that used in x86_cpuid_copy_to_buffer(). Also follow this for the > extended main leaves then. > > Fixes: 1bd2b750537b ("libx86: Fix 32bit stubdom build of x86_cpuid_policy_fill_native()") > Fixes: 97e4ebdcd765 ("x86/CPUID: support leaf 7 subleaf 1 / AVX512_BF16") > Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- a/xen/include/xen/lib/x86/cpuid.h +++ b/xen/include/xen/lib/x86/cpuid.h @@ -181,8 +181,7 @@ struct cpuid_policy uint32_t _7d0; struct { DECL_BITFIELD(7d0); }; }; - }; - struct { + /* Subleaf 1. */ union { uint32_t _7a1; --- a/xen/lib/x86/cpuid.c +++ b/xen/lib/x86/cpuid.c @@ -71,8 +71,8 @@ void x86_cpuid_policy_fill_native(struct unsigned int i; cpuid_leaf(0, &p->basic.raw[0]); - for ( i = 1; i < min_t(unsigned int, ARRAY_SIZE(p->basic.raw), - p->basic.max_leaf); ++i ) + for ( i = 1; i <= MIN(p->basic.max_leaf, + ARRAY_SIZE(p->basic.raw) - 1); ++i ) { switch ( i ) { @@ -116,8 +116,8 @@ void x86_cpuid_policy_fill_native(struct { cpuid_count_leaf(7, 0, &p->feat.raw[0]); - for ( i = 1; i < min_t(unsigned int, ARRAY_SIZE(p->feat.raw), - p->feat.max_subleaf); ++i ) + for ( i = 1; i <= MIN(p->feat.max_subleaf, + ARRAY_SIZE(p->feat.raw) - 1); ++i ) cpuid_count_leaf(7, i, &p->feat.raw[i]); } @@ -172,8 +172,8 @@ void x86_cpuid_policy_fill_native(struct /* Extended leaves. */ cpuid_leaf(0x80000000, &p->extd.raw[0]); - for ( i = 1; i < min_t(unsigned int, ARRAY_SIZE(p->extd.raw), - p->extd.max_leaf + 1 - 0x80000000); ++i ) + for ( i = 1; i <= MIN(p->extd.max_leaf & 0xffffU, + ARRAY_SIZE(p->extd.raw) - 1); ++i ) cpuid_leaf(0x80000000 + i, &p->extd.raw[i]); x86_cpuid_policy_recalc_synth(p);
For one, subleaves within the respective union shouldn't live in separate sub-structures. And then x86_cpuid_policy_fill_native() should, as it did originally, iterate over all subleaves here as well as over all main leaves. Switch to using a "<= MIN()"-based approach similar to that used in x86_cpuid_copy_to_buffer(). Also follow this for the extended main leaves then. Fixes: 1bd2b750537b ("libx86: Fix 32bit stubdom build of x86_cpuid_policy_fill_native()") Fixes: 97e4ebdcd765 ("x86/CPUID: support leaf 7 subleaf 1 / AVX512_BF16") Signed-off-by: Jan Beulich <jbeulich@suse.com>