From: Paolo Bonzini <pbonzini@redhat.com>
To: Andrew Jones <drjones@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH] kvm-all: PAGE_SIZE should be real host page size
Date: Tue, 10 Nov 2015 17:15:43 +0100 [thread overview]
Message-ID: <5642182F.8020108@redhat.com> (raw)
In-Reply-To: <20151110155728.GB3452@hawk.localdomain>
On 10/11/2015 16:57, Andrew Jones wrote:
> On Tue, Nov 10, 2015 at 04:41:16PM +0100, Paolo Bonzini wrote:
>>
>>
>> On 10/11/2015 01:23, Andrew Jones wrote:
>>> Just noticed this while grepping TARGET_PAGE_SIZE for an unrelated
>>> reason. I didn't use qemu_real_host_page_size as kvm_set_phys_mem()
>>> does, because we'd need to make sure page_size_init() has run first.
>>>
>>> Signed-off-by: Andrew Jones <drjones@redhat.com>
>>> ---
>>> kvm-all.c | 6 ++++--
>>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/kvm-all.c b/kvm-all.c
>>> index 1bc12737723c3..de9ff5971fb3b 100644
>>> --- a/kvm-all.c
>>> +++ b/kvm-all.c
>>> @@ -45,8 +45,10 @@
>>> #include <sys/eventfd.h>
>>> #endif
>>>
>>> -/* KVM uses PAGE_SIZE in its definition of COALESCED_MMIO_MAX */
>>> -#define PAGE_SIZE TARGET_PAGE_SIZE
>>> +/* KVM uses PAGE_SIZE in its definition of KVM_COALESCED_MMIO_MAX. We
>>> + * need to use the real host PAGE_SIZE, as that's what KVM will use.
>>> + */
>>> +#define PAGE_SIZE getpagesize()
>>>
>>> //#define DEBUG_KVM
>>>
>>>
>>
>> Is this a bugfix or just a cleanup? If the former, on which targets?
>
> It's a bugfix for any targets that have a TARGET_PAGE_SIZE !=
> real-host-page-size. For example ARM has TARGET_PAGE_SIZE set to 1024,
> even when the host is using 4k or 64k pages. However, I didn't find this
> due to a bug, because on ARM I'm not using emulated devices that make
> use of the coalesced-mmio feature at this time.
>
> Thanks,
> drew
>
>>
>> Paolo
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
Ok, applied (2.6 only unless I gather more urgent patches).
Paolo
next prev parent reply other threads:[~2015-11-10 16:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-10 0:23 [Qemu-devel] [PATCH] kvm-all: PAGE_SIZE should be real host page size Andrew Jones
2015-11-10 15:41 ` Paolo Bonzini
2015-11-10 15:57 ` Andrew Jones
2015-11-10 16:15 ` Paolo Bonzini [this message]
2015-11-10 16:29 ` Peter Maydell
2015-11-10 16:59 ` Andrew Jones
2015-11-10 17:02 ` Peter Maydell
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