From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: peter.maydell@linaro.org, pbonzini@redhat.com,
qemu-devel@nongnu.org, mst@redhat.com
Subject: Re: [Qemu-devel] [PATCH 1/2] memory: Align and add helper for comparing MemoryRegionSections
Date: Wed, 14 Aug 2019 19:35:41 +0200 [thread overview]
Message-ID: <64416580-ee29-8d75-4ad6-c1453d70afd6@redhat.com> (raw)
In-Reply-To: <20190814172545.GS2920@work-vm>
On 8/14/19 7:25 PM, Dr. David Alan Gilbert wrote:
> * Philippe Mathieu-Daudé (philmd@redhat.com) wrote:
>> Hi David,
>>
>> On 8/13/19 12:29 PM, Dr. David Alan Gilbert (git) wrote:
>>> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>>>
>>> MemoryRegionSection includes an Int128 'size' field;
>>> on some platforms the compiler causes an alignment of this to
>>> a 128bit boundary, leaving 8 bytes of dead space.
>>> This deadspace can be filled with junk.
>>>
>>> Move the size field to the top avoiding unnecsssary alignment
>>
>> "unnecessary"
>
> Oops thanks.
>
>> This is enough change to be in its own commit.
>>
>> ---
>>
>>> and provide an 'eq' routine to safely compare MRS's.
>>
>> This is another change, and should be squashed in the next patch IMO.
>
> OK, what I'll do is I'll split this one into two ; I feel better
> having the extra function here separate from the next commit.
Thanks, feel free to add to both:
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Doesn't Clang warn about unused 'static inline' btw?
>
> I was using gcc; but we seem to have loads of static inline's - what
> would make this one different?
I guess I was confused with 'static (no-inline)' :)
>>>
>>> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>>> ---
>>> include/exec/memory.h | 14 +++++++++++++-
>>> 1 file changed, 13 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>>> index 606250172a..ce62e847bd 100644
>>> --- a/include/exec/memory.h
>>> +++ b/include/exec/memory.h
>>> @@ -487,15 +487,27 @@ static inline FlatView *address_space_to_flatview(AddressSpace *as)
>>> * @nonvolatile: this section is non-volatile
>>> */
>>> struct MemoryRegionSection {
>>> + Int128 size;
>>> MemoryRegion *mr;
>>> FlatView *fv;
>>> hwaddr offset_within_region;
>>> - Int128 size;
>>> hwaddr offset_within_address_space;
>>> bool readonly;
>>> bool nonvolatile;
>>> };
>>>
>>> +static inline bool MemoryRegionSection_eq(MemoryRegionSection *a,
>>> + MemoryRegionSection *b)
>>> +{
>>> + return a->mr == b->mr &&
>>> + a->fv == b->fv &&
>>> + a->offset_within_region == b->offset_within_region &&
>>> + a->offset_within_address_space == b->offset_within_address_space &&
>>> + int128_eq(a->size, b->size) &&
>>> + a->readonly == b->readonly &&
>>> + a->nonvolatile == b->nonvolatile;
>>> +}
>>> +
>>> /**
>>> * memory_region_init: Initialize a memory region
>>> *
>>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
next prev parent reply other threads:[~2019-08-14 17:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 10:29 [Qemu-devel] [PATCH 0/2] Fix MemoryRegionSection alignment and comparison Dr. David Alan Gilbert (git)
2019-08-13 10:29 ` [Qemu-devel] [PATCH 1/2] memory: Align and add helper for comparing MemoryRegionSections Dr. David Alan Gilbert (git)
2019-08-13 12:58 ` Philippe Mathieu-Daudé
2019-08-14 17:25 ` Dr. David Alan Gilbert
2019-08-14 17:35 ` Philippe Mathieu-Daudé [this message]
2019-08-14 17:44 ` Dr. David Alan Gilbert
2019-08-13 10:29 ` [Qemu-devel] [PATCH 2/2] vhost: Fix memory region section comparison Dr. David Alan Gilbert (git)
2019-08-13 12:06 ` [Qemu-devel] [PATCH 0/2] Fix MemoryRegionSection alignment and comparison Paolo Bonzini
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