On Wed, Nov 16, 2022 at 06:48:43PM +0000, Sean Christopherson wrote: > On Wed, Nov 16, 2022, Andy Lutomirski wrote: > > > > > > On Tue, Oct 25, 2022, at 8:13 AM, Chao Peng wrote: > > > diff --git a/Documentation/virt/kvm/api.rst > > > b/Documentation/virt/kvm/api.rst > > > index f3fa75649a78..975688912b8c 100644 > > > --- a/Documentation/virt/kvm/api.rst > > > +++ b/Documentation/virt/kvm/api.rst > > > @@ -6537,6 +6537,29 @@ array field represents return values. The > > > userspace should update the return > > > values of SBI call before resuming the VCPU. For more details on > > > RISC-V SBI > > > spec refer, https://github.com/riscv/riscv-sbi-doc. > > > > > > +:: > > > + > > > + /* KVM_EXIT_MEMORY_FAULT */ > > > + struct { > > > + #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1 << 0) > > > + __u32 flags; > > > + __u32 padding; > > > + __u64 gpa; > > > + __u64 size; > > > + } memory; > > > + > > > > Would it make sense to also have a field for the access type (read, write, > > execute, etc)? I realize that shared <-> private conversion doesn't strictly > > need this, but it seems like it could be useful for logging failures and also > > for avoiding a second immediate fault if the type gets converted but doesn't > > have the right protection yet. > > I don't think a separate field is necessary, that info can be conveyed via flags. > Though maybe we should go straight to a u64 for flags. Yeah, I can do that. > Hmm, and maybe avoid bits > 0-3 so that if/when RWX info is conveyed the flags can align with > PROT_{READ,WRITE,EXEC} and the EPT flags, e.g. You mean avoiding bits 0-2, right, bit3 is not so special and can be used for KVM_MEMORY_EXIT_FLAG_PRIVATE. Chao > > KVM_MEMORY_EXIT_FLAG_READ (1 << 0) > KVM_MEMORY_EXIT_FLAG_WRITE (1 << 1) > KVM_MEMORY_EXIT_FLAG_EXECUTE (1 << 2) > > > (Obviously, if this were changed, KVM would need the ability to report that > > it doesn't actually know the mode.) > > > > --Andy
