On Wed, Nov 11, 2015 at 10:45:00PM +0530, Aravinda Prasad wrote: > This series of patches add support for FWNMI in PowerKVM guests. > > Memory error such as bit flips that cannot be corrected > by hardware is passed on to the kernel for handling > by raising machine check exception (an NMI). Upon such > machine check exception, if the address in error belongs > to guest then KVM causes a guest exit with KVM_EXIT_NMI > exit reason [1]. > > This patch series adds functionality to pass on such > machine check exception to the guest kernel by suitably > handling KVM_EXIT_NMI exit and building the error log. > This patch series explores the alternate design > discussed in the QEMU mailing list [2], [3]. > > In earlier design [2] KVM invoked guest's NMI interrupt > vector 0x200 upon machine check exception, while QEMU > patched 0x200 vector to issue hcall to facilitate > building and copying of error log into RTAS space. > > The new design simplifies couple of things. Thanks to > David Gibson for the suggestion: > > - Eliminates patching of 0x200 interrupt vector from > QEMU, hence, trampoline not required > - Avoids introducing a new private hcall to be called > from guest's 0x200 vector to enable QEMU to build > error log > - Simplifies re-trying by other processors when one > of the processor is consuming/processing the error > log. > > [1] http://marc.info/?l=kvm-ppc&m=144726114408289 > [2] https://lists.nongnu.org/archive/html/qemu-devel/2014-11/msg00813.html > [3] > https://lists.nongnu.org/archive/html/qemu-devel/2015-08/msg00898.html
This looks basically good, although I have some concerns noted in replies to patches 3 & 4. We can't merge this, though, until the prerequisite kernel and SLOF patches are merged, so this won't make it into 2.5 (hard freeze today). -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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