Messages in this thread | | | Subject | Re: [PATCH v7 1/9] Documentation: Introduce EPT based Subpage Protection and related ioctls | From | Paolo Bonzini <> | Date | Thu, 21 Nov 2019 11:02:56 +0100 |
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On 19/11/19 09:49, Yang Weijiang wrote: > + > +#define SUBPAGE_MAX_BITMAP 64
Please rename this to KVM_SUBPAGE_MAX_PAGES
> +struct kvm_subpage_info { > + __u64 gfn; /* the first page gfn of the contiguous pages */ > + __u64 npages; /* number of 4K pages */
This can be
u32 npages; u32 flags;
Check that the flags are 0, and fail the ioctl if they aren't. This will make it easy to extend the API in the future.
> + __u32 access_map[SUBPAGE_MAX_BITMAP]; /* sub-page write-access bitmap array */ > +};
Please make this access_map[0], since the number of entries actually depends on npages.
Likewise, kvm_arch_vm_ioctl should read the header first, then allocate memory for the access_map and read into it. It's probably simpler if you make kvm_vm_ioctl_get_subpages/kvm_vm_ioctl_set_subpages take parameters like
int kvm_vm_ioctl_get_subpages(struct kvm *kvm, u64 gfn, u32 npages, u32 *access_map); int kvm_vm_ioctl_set_subpages(struct kvm *kvm, u64 gfn, u32 npages, u32 *access_map);
Thanks,
Paolo
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