On 12/23/2010 04:28 PM, Marcelo Tosatti wrote:
On Wed, Dec 22, 2010 at 10:52:51AM +0800, Huang Ying wrote: > In Linux kernel HWPoison processing implementation, the virtual > address in processes mapping the error physical memory page is marked > as HWPoison. So that, the further accessing to the virtual > address will kill corresponding processes with SIGBUS. > > If the error physical memory page is used by a KVM guest, the SIGBUS > will be sent to QEMU, and QEMU will simulate a MCE to report that > memory error to the guest OS. If the guest OS can not recover from > the error (for example, the page is accessed by kernel code), guest OS > will reboot the system. But because the underlying host virtual > address backing the guest physical memory is still poisoned, if the > guest system accesses the corresponding guest physical memory even > after rebooting, the SIGBUS will still be sent to QEMU and MCE will be > simulated. That is, guest system can not recover via rebooting. > > In fact, across rebooting, the contents of guest physical memory page > need not to be kept. We can allocate a new host physical page to > back the corresponding guest physical address. > > This patch fixes this issue in QEMU-KVM via invoke the unpoison > mechanism implemented in Linux kernel to clear the corresponding page > table entry, so that make it possible to allocate a new page to > recover the issue. > > Signed-off-by: Huang Ying<ying.hu...@intel.com>> +struct HWPoisonPage; > +typedef struct HWPoisonPage HWPoisonPage; > +struct HWPoisonPage > +{ > + void *vaddr; > + QLIST_ENTRY(HWPoisonPage) list; > +}; > + > +static QLIST_HEAD(hwpoison_page_list, HWPoisonPage) hwpoison_page_list = > + QLIST_HEAD_INITIALIZER(hwpoison_page_list); > + > +static void kvm_unpoison_all(void *param) > +{ > + HWPoisonPage *page, *next_page; > + unsigned long address; > + KVMState *s = param; > + > + QLIST_FOREACH_SAFE(page,&hwpoison_page_list, list, next_page) { > + address = (unsigned long)page->vaddr; > + QLIST_REMOVE(page, list); > + kvm_vm_ioctl(s, KVM_UNPOISON_ADDRESS, address); > + qemu_free(page); > + } > +} Can't you free and reallocate all guest memory instead, on reboot, if there's a hwpoisoned page? Then you don't need this interface.
Alternatively, MADV_DONTNEED? We already use it for ballooning. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
