On Thu, 27 Jan 2011 15:29:05 +0800 Huang Ying <ying.huang@xxxxxxxxx> wrote: > Hi, Andrew, > > On Thu, 2011-01-20 at 23:50 +0800, Marcelo Tosatti wrote: > > On Mon, Jan 17, 2011 at 08:47:39AM +0800, Huang Ying wrote: > > > Hi, Andrew, > > > > > > On Sun, 2011-01-16 at 23:35 +0800, Avi Kivity wrote: > > > > On 01/14/2011 03:37 AM, Huang Ying wrote: > > > > > On Thu, 2011-01-13 at 18:43 +0800, Avi Kivity wrote: > > > > > > On 01/13/2011 10:42 AM, Huang Ying wrote: > > > > > > > Make __get_user_pages return -EHWPOISON for HWPOISON page only if > > > > > > > FOLL_HWPOISON is specified. With this patch, the interested callers > > > > > > > can distinguish HWPOISON page from general FAULT page, while other > > > > > > > callers will still get -EFAULT for pages, so the user space interface > > > > > > > need not to be changed. > > > > > > > > > > > > > > get_user_pages_hwpoison is added as a variant of get_user_pages that > > > > > > > can return -EHWPOISON for HWPOISON page. > > > > > > > > > > > > > > This feature is needed by KVM, where UCR MCE should be relayed to > > > > > > > guest for HWPOISON page, while instruction emulation and MMIO will be > > > > > > > tried for general FAULT page. > > > > > > > > > > > > > > The idea comes from Andrew Morton. > > > > > > > > > > > > > > Signed-off-by: Huang Ying<ying.huang@xxxxxxxxx> > > > > > > > Cc: Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx> > > > > > > > > > > > > > > +#ifdef CONFIG_MEMORY_FAILURE > > > > > > > +int get_user_pages_hwpoison(struct task_struct *tsk, struct mm_struct *mm, > > > > > > > + unsigned long start, int nr_pages, int write, > > > > > > > + int force, struct page **pages, > > > > > > > + struct vm_area_struct **vmas); > > > > > > > +#else > > > > > > > > > > > > Since we'd also like to add get_user_pages_noio(), perhaps adding a > > > > > > flags field to get_user_pages() is better. > > > > > > > > > > Or export __get_user_pages()? > > > > > > > > That's better, yes. > > > > > > Do you think it is a good idea to export __get_user_pages() instead of > > > adding get_user_pages_noio() and get_user_pages_hwpoison()? > > > > Better Andrew and/or Linus should decide it. > > We really need your comments about this. > Export __get_user_pages(), I guess. We don't need hwpoison/kvm-specific stuff in mm/memory.c and get_user_pages_hwpoison()/get_user_pages_noio() are very thin wrappers. The number of args to these functions is getting nutty - you'll probably find that it is beneficial to inline these wrapepr functions, if the number of callsites is small. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
