| Message ID | 1489744633-28760-5-git-send-email-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
>>> On 17.03.17 at 10:57, <paul.durrant@citrix.com> wrote: > --- a/xen/arch/x86/hvm/viridian.c > +++ b/xen/arch/x86/hvm/viridian.c > @@ -119,14 +119,16 @@ void cpuid_viridian_leaves(const struct vcpu *v, uint32_t leaf, > switch ( leaf ) > { > case 0: > + /* See section 2.4.1 of the specification */ > res->a = 0x40000006; /* Maximum leaf */ > - res->b = 0x7263694d; /* Magic numbers */ > - res->c = 0x666F736F; > - res->d = 0x76482074; > + res->b = *(uint32_t *)"Micr"; > + res->c = *(uint32_t *)"osof"; > + res->d = *(uint32_t *)"t Hv"; > break; > > case 1: > - res->a = 0x31237648; /* Version number */ > + /* See section 2.4.2 of the specification */ > + res->a = *(uint32_t *)"Hv#1"; > break; You're the maintainer of the code, so I can't really reject this, but (ugly) casts don't seem any better to me, the more that they cast away constness. Would memcpy(&res->a, "Hv#1", 4); etc be acceptable to you? Jan
> -----Original Message----- > From: Jan Beulich [mailto:JBeulich@suse.com] > Sent: 20 March 2017 12:15 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>; xen- > devel@lists.xenproject.org > Subject: Re: [PATCH 4/7] x86/viridian: get rid of the magic numbers in CPUID > leaves 1 and 2 > > >>> On 17.03.17 at 10:57, <paul.durrant@citrix.com> wrote: > > --- a/xen/arch/x86/hvm/viridian.c > > +++ b/xen/arch/x86/hvm/viridian.c > > @@ -119,14 +119,16 @@ void cpuid_viridian_leaves(const struct vcpu *v, > uint32_t leaf, > > switch ( leaf ) > > { > > case 0: > > + /* See section 2.4.1 of the specification */ > > res->a = 0x40000006; /* Maximum leaf */ > > - res->b = 0x7263694d; /* Magic numbers */ > > - res->c = 0x666F736F; > > - res->d = 0x76482074; > > + res->b = *(uint32_t *)"Micr"; > > + res->c = *(uint32_t *)"osof"; > > + res->d = *(uint32_t *)"t Hv"; > > break; > > > > case 1: > > - res->a = 0x31237648; /* Version number */ > > + /* See section 2.4.2 of the specification */ > > + res->a = *(uint32_t *)"Hv#1"; > > break; > > You're the maintainer of the code, so I can't really reject this, but > (ugly) casts don't seem any better to me, the more that they cast > away constness. Would > > memcpy(&res->a, "Hv#1", 4); > > etc be acceptable to you? I'm ok with that. Paul > > Jan
diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c index 433035e..4151ba5 100644 --- a/xen/arch/x86/hvm/viridian.c +++ b/xen/arch/x86/hvm/viridian.c @@ -119,14 +119,16 @@ void cpuid_viridian_leaves(const struct vcpu *v, uint32_t leaf, switch ( leaf ) { case 0: + /* See section 2.4.1 of the specification */ res->a = 0x40000006; /* Maximum leaf */ - res->b = 0x7263694d; /* Magic numbers */ - res->c = 0x666F736F; - res->d = 0x76482074; + res->b = *(uint32_t *)"Micr"; + res->c = *(uint32_t *)"osof"; + res->d = *(uint32_t *)"t Hv"; break; case 1: - res->a = 0x31237648; /* Version number */ + /* See section 2.4.2 of the specification */ + res->a = *(uint32_t *)"Hv#1"; break; case 2:
The numbers correspond to ASCII characters so just use appropriate character strings directly. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Jan Beulich <jbeulich@suse.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> --- xen/arch/x86/hvm/viridian.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)