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[Xen-devel] [PATCH] x86: Hyper-V clock source's offset should be signed

Wei Liu posted 1 patch 6 years, 1 month ago
Failed in applying to current master (apply log)
xen/arch/x86/time.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
[Xen-devel] [PATCH] x86: Hyper-V clock source's offset should be signed
Posted by Wei Liu 6 years, 1 month ago 
Fixes: 685d16bd5 (x86: implement Hyper-V clock source)
Signed-off-by: Wei Liu <liuwe@microsoft.com>
---
I discover this stupid mistake when I work on extracting common code
from viridian and the clock source implementation.
---
 xen/arch/x86/time.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index a3c9b927e8..bbcc9b10b8 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -698,7 +698,8 @@ static int64_t __init init_hyperv_timer(struct platform_timesource *pts)
 
 static inline uint64_t read_hyperv_timer(void)
 {
-    uint64_t scale, offset, ret, tsc;
+    uint64_t scale, ret, tsc;
+    int64_t offset;
     uint32_t seq;
     const struct ms_hyperv_tsc_page *tsc_page = hyperv_tsc;
 
-- 
2.20.1


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Re: [Xen-devel] [PATCH] x86: Hyper-V clock source's offset should be signed
Posted by Andrew Cooper 6 years, 1 month ago 
On 20/12/2019 19:47, Wei Liu wrote:
> Fixes: 685d16bd5 (x86: implement Hyper-V clock source)
> Signed-off-by: Wei Liu <liuwe@microsoft.com>
> ---
> I discover this stupid mistake when I work on extracting common code
> from viridian and the clock source implementation.

Does it make a practical difference?

> ---
>  xen/arch/x86/time.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
> index a3c9b927e8..bbcc9b10b8 100644
> --- a/xen/arch/x86/time.c
> +++ b/xen/arch/x86/time.c
> @@ -698,7 +698,8 @@ static int64_t __init init_hyperv_timer(struct platform_timesource *pts)
>  
>  static inline uint64_t read_hyperv_timer(void)

Also, this function is only ever accessed via pointer.  The inline can't
be satisfied at all.

~Andrew

>  {
> -    uint64_t scale, offset, ret, tsc;
> +    uint64_t scale, ret, tsc;
> +    int64_t offset;
>      uint32_t seq;
>      const struct ms_hyperv_tsc_page *tsc_page = hyperv_tsc;
>  


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Re: [Xen-devel] [PATCH] x86: Hyper-V clock source's offset should be signed
Posted by Wei Liu 6 years, 1 month ago 
On Fri, 20 Dec 2019 at 19:57, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
>
> On 20/12/2019 19:47, Wei Liu wrote:
> > Fixes: 685d16bd5 (x86: implement Hyper-V clock source)
> > Signed-off-by: Wei Liu <liuwe@microsoft.com>
> > ---
> > I discover this stupid mistake when I work on extracting common code
> > from viridian and the clock source implementation.
>
> Does it make a practical difference?
>

Probably not. The specs says that field is signed, so our code should
reflect that.

> > ---
> >  xen/arch/x86/time.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
> > index a3c9b927e8..bbcc9b10b8 100644
> > --- a/xen/arch/x86/time.c
> > +++ b/xen/arch/x86/time.c
> > @@ -698,7 +698,8 @@ static int64_t __init init_hyperv_timer(struct platform_timesource *pts)
> >
> >  static inline uint64_t read_hyperv_timer(void)
>
> Also, this function is only ever accessed via pointer.  The inline can't
> be satisfied at all.
>

I can drop the inline here.

Wei.

> ~Andrew
>
> >  {
> > -    uint64_t scale, offset, ret, tsc;
> > +    uint64_t scale, ret, tsc;
> > +    int64_t offset;
> >      uint32_t seq;
> >      const struct ms_hyperv_tsc_page *tsc_page = hyperv_tsc;
> >
>

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Re: [Xen-devel] [PATCH] x86: Hyper-V clock source's offset should be signed
Posted by Andrew Cooper 6 years, 1 month ago 
On 20/12/2019 20:02, Wei Liu wrote:
> On Fri, 20 Dec 2019 at 19:57, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
>> On 20/12/2019 19:47, Wei Liu wrote:
>>> Fixes: 685d16bd5 (x86: implement Hyper-V clock source)
>>> Signed-off-by: Wei Liu <liuwe@microsoft.com>
>>> ---
>>> I discover this stupid mistake when I work on extracting common code
>>> from viridian and the clock source implementation.
>> Does it make a practical difference?
>>
> Probably not. The specs says that field is signed, so our code should
> reflect that.

Fair enough.  Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> (with
the inline fix as well)

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Re: [Xen-devel] [PATCH] x86: Hyper-V clock source's offset should be signed
Posted by Wei Liu 6 years, 1 month ago 
On Fri, Dec 20, 2019 at 08:04:12PM +0000, Andrew Cooper wrote:
> On 20/12/2019 20:02, Wei Liu wrote:
> > On Fri, 20 Dec 2019 at 19:57, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
> >> On 20/12/2019 19:47, Wei Liu wrote:
> >>> Fixes: 685d16bd5 (x86: implement Hyper-V clock source)
> >>> Signed-off-by: Wei Liu <liuwe@microsoft.com>
> >>> ---
> >>> I discover this stupid mistake when I work on extracting common code
> >>> from viridian and the clock source implementation.
> >> Does it make a practical difference?
> >>
> > Probably not. The specs says that field is signed, so our code should
> > reflect that.
> 
> Fair enough.  Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> (with
> the inline fix as well)

Thanks. I will commit this now.

Wei.

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