On 28.08.14 08:12, Aravinda Prasad wrote: > > > On Wednesday 27 August 2014 03:20 PM, Alexander Graf wrote: >> >> >> On 25.08.14 15:45, Aravinda Prasad wrote: >>> Whenever there is a physical memory error due to bit >>> flips, which cannot be corrected by hardware, the error >>> is passed on to the kernel. If the memory address in >>> error belongs to guest address space then guest kernel >>> is responsible to take action. Hence the error is passed >>> on to guest via KVM by invoking 0x200 NMI vector. >>> >>> However, guest OS, as per PAPR, expects an error log >>> upon such error. This patch registers a new hcall >>> which is issued from 0x200 interrupt vector and builds >>> the error log, copies the error log to rtas space and >>> passes the address of the error log to guest >>> >>> Enhancement to KVM to perform above functionality is >>> already in upstream kernel. >>> >>> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com> >> >> Why do we have to maintain the error log inside the rtas blob? Can't we >> just create a fixed MMIO region that is backed by an error log device in >> QEMU? >> >> Then this call would just always return that specific address and we'd >> also have a single file that deals with all of the error reporting. > > PAPR requires error log to be inside rtas space. Hence guest OS > explicitly checks if error log is inside rtas space. > > VALID_FWNMI_BUFFER does this check inside fwnmi_get_errinfo() in the kernel.
So why not put it at 0x7000 then? Alex
