On Fri, Apr 22, 2022 at 01:06:25PM +0200, Paolo Bonzini wrote: > On 4/22/22 12:56, Chao Peng wrote: > > /* memfile notifier flags */ > > #define MFN_F_USER_INACCESSIBLE 0x0001 /* memory allocated in the file is inaccessible from userspace (e.g. read/write/mmap) */ > > #define MFN_F_UNMOVABLE 0x0002 /* memory allocated in the file is unmovable */ > > #define MFN_F_UNRECLAIMABLE 0x0003 /* memory allocated in the file is unreclaimable (e.g. via kswapd or any other pathes) */ > > You probably mean BIT(0/1/2) here. Right, it's BIT(n), Thanks. Chao > > Paolo > > > When memfile_notifier is being registered, memfile_register_notifier will > > need check these flags. E.g. for MFN_F_USER_INACCESSIBLE, it fails when > > previous mmap-ed mapping exists on the fd (I'm still unclear on how to do > > this). When multiple consumers are supported it also need check all > > registered consumers to see if any conflict (e.g. all consumers should have > > MFN_F_USER_INACCESSIBLE set). Only when the register succeeds, the fd is > > converted into a private fd, before that, the fd is just a normal (shared) > > one. During this conversion, the previous data is preserved so you can put > > some initial data in guest pages (whether the architecture allows this is > > architecture-specific and out of the scope of this patch).
