On 08/10/2012 09:14 PM, Marcelo Tosatti wrote: > On Tue, Aug 07, 2012 at 05:47:15PM +0800, Xiao Guangrong wrote: >> Changelog: >> - introduce KVM_PFN_ERR_RO_FAULT instead of dummy page >> - introduce KVM_HVA_ERR_BAD and optimize error hva indicators >> >> The test case can be found at: >> http://lkml.indiana.edu/hypermail/linux/kernel/1207.2/00819/migrate-perf.tar.bz2 >> >> In current code, if we map a readonly memory space from host to guest >> and the page is not currently mapped in the host, we will get a fault-pfn >> and async is not allowed, then the vm will crash. >> >> As Avi's suggestion, We introduce readonly memory region to map ROM/ROMD >> to the guest, read access is happy for readonly memslot, write access on >> readonly memslot will cause KVM_EXIT_MMIO exit. > > Memory slots whose QEMU mapping is write protected is supported > today, as long as there are no write faults. > > What prevents the use of mmap(!MAP_WRITE) to handle read-only memslots > again? Userspace may want to modify the ROM (for example, when programming a flash device). It is also possible to map an hva range rw through one slot and ro through another. -- 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 majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
