On Tue, 17 Apr 2018 14:08:59 -0400
Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:
On 04/17/2018 11:21 AM, Cornelia Huck wrote:Ah yes, with "current" I referred to current upstream.
On Tue, 17 Apr 2018 10:26:57 -0400I guess that depends upon what you mean by current code. If you are talking
Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:
On 04/17/2018 06:10 AM, Cornelia Huck wrote:Hm, the current code does a quick exit if bit 76 is not set, doesn't
On Tue, 17 Apr 2018 09:49:58 +0200The crycb is set up regardless of whether STFLE.76 (MSAX3) is
"Harald Freudenberger" <FREUDE@xxxxxxxxxx> wrote:
Didn't we say that when APXA is not available there is no Crypto support[Going by the code, as I don't have access to the architecture]
for KVM ?
Current status seems to be:
- setup crycb if facility 76 is available (that's MSAX3, I guess?)
installed or not.
it?
about the code as it is distributed today - i.e., before my patch series -
then you are correct. This patch changes that; it initializes the
kvm->arch.crypto.crycbd to point to the CRYCB, then clears the format bits
(kvm->arch.crypto.crycbd &= ~(CRYCB_FORMAT_MASK)) which is the same as
setting the CRYCB format to format 0. It is only after this that the
check is done to determine whether STFLE.76 is set.
OK, great.It also implements what is stated in the architecture doc.With the format selection you outlined above, I guess. Makes sense from- use format 2 if APXA is available, else use format 1Use format 0 if MSAX3 is not available
Use format 1 if MSAX3 is available but APXA is not
Use format 2 if MSAX3 and APXA is available
From Tony's patch description, the goal seems to be:Yes, that is true
- setup crycb even if MSAX3 is not available
So my understanding is that we use APXA only to decide on the format ofYes, that is true
the crycb, but provide it in any case?
my point of view (just looking at the source code).
So I guess we should not introduce a tie-in then (unless it radicallyI don't see any reason to do that from an architectural perspective.But would it actually make sense to tie vfio-ap to APXA? This needs to(Not providing a crycb if APXA is not available would be loss ofThis would require a change to enabling the CPU model feature for
functionality, I guess? Deciding not to provide vfio-ap if APXA is not
available is a different game, of course.)
AP.
be answered by folks with access to the architecture :)
One can access AP devices whether APXA is installed or not, it just limits
the range of devices that can be addressed
simplifies the code...)