On Tuesday 11 November 2014 08:54 AM, David Gibson wrote:
[..] > > So, this may not still be possible depending on whether the KVM side > of this is already merged, but it occurs to me that there's a simpler > way. > > Rather than mucking about with having to update the hypervisor on the > RTAS location, they have qemu copy the code out of RTAS, patch it and > copy it back into the vector, you could instead do this: > > 1. Make KVM instead of immediately delivering a 0x200 for a guest > machine check, cause a special exit to qemu. > > 2. Have the register-nmi RTAS call store the guest side MC handler > address in the spapr structure, but perform no actual guest code > patching. > > 3. Allocate the error log buffer independently from the RTAS blob, > so qemu always knows where it is. > > 4. When qemu gets the MC exit condition, instead of going via a > patched 0x200 vector, just directly set the guest register state and > jump straight into the guest side MC handler. > Before I proceed further I would like to know what others think about the approach proposed above (except for step 3 - as per PAPR the error log buffer should be part of RTAS blob and hence we cannot have error log buffer independent of RTAS blob). Alex, Alexey, Ben: Any thoughts? -- Regards, Aravinda
