On 05/04/2010 03:00 PM, Roedel, Joerg wrote:
On Tue, May 04, 2010 at 05:50:50AM -0400, Avi Kivity wrote:
On 05/04/2010 12:45 PM, Avi Kivity wrote:
Just a silly bug. kvm_pdptr_read() can cause a guest memory read on
svm, in this case with the mmu lock taken. I'll post something to fix
it.
I guess this was not reported because most svm machines have npt, and
this requires npt=0 to trigger. Nonpae paging disables npt, so you were
hit. Interestingly, nsvm makes it more likely to appear, since npt on
i386+pae will need the pdptrs.
Hmm, actually it happened on 32 bit with npt enabled. I think this
can trigger when mmu_alloc_roots is called for an pae guest because it
accidentially tries read the root_gfn from the guest before it figures
out that it runs with tdp and omits the gfn read from the guest.
Yes. I had a patchset which moved the 'direct' calculation before, and
skipped root_gfn if it was direct, but it was broken. If you like I can
resurrect it, but it may interfere with your work.
--
error compiling committee.c: too many arguments to function
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