On 12/12/20 00:54, Sean Christopherson wrote:
On Fri, Dec 11, 2020, Paolo Bonzini wrote:
From: "Maciej S. Szmigiero" <maciej.szmigiero@xxxxxxxxxx>
Commit cae7ed3c2cb0 ("KVM: x86: Refactor the MMIO SPTE generation handling")
cleaned up the computation of MMIO generation SPTE masks, however it
introduced a bug how the upper part was encoded:
SPTE bits 52-61 were supposed to contain bits 10-19 of the current
generation number, however a missing shift encoded bits 1-10 there instead
(mostly duplicating the lower part of the encoded generation number that
then consisted of bits 1-9).
In the meantime, the upper part was shrunk by one bit and moved by
subsequent commits to become an upper half of the encoded generation number
(bits 9-17 of bits 0-17 encoded in a SPTE).
In addition to the above, commit 56871d444bc4 ("KVM: x86: fix overlap between SPTE_MMIO_MASK and generation")
has changed the SPTE bit range assigned to encode the generation number and
the total number of bits encoded but did not update them in the comment
attached to their defines, nor in the KVM MMU doc.
Let's do it here, too, since it is too trivial thing to warrant a separate
commit.
Fixes: cae7ed3c2cb0 ("KVM: x86: Refactor the MMIO SPTE generation handling")
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx>
Message-Id: <156700708db2a5296c5ed7a8b9ac71f1e9765c85.1607129096.git.maciej.szmigiero@xxxxxxxxxx>
Cc: stable@xxxxxxxxxx
I assume you want stable@xxxxxxxxxxxxxxx?
I do.
[Reorganize macros so that everything is computed from the bit ranges. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
Compared to v2 by Maciej, I chose to keep GEN_MASK's argument calculated,
Booooo. :-D
But I explained why. :)
Paolo
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
but assert on the number of bits in the low and high parts. This is
because any change on those numbers will have to be reflected in the
comment, and essentially we're asserting that the comment is up-to-date.
