Messages in this thread | | | Date | Fri, 22 Apr 2022 13:06:25 +0200 | Subject | Re: [PATCH v5 00/13] KVM: mm: fd-based approach for supporting KVM guest private memory | From | Paolo Bonzini <> |
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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.
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).
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