diff options
| author | Sean Christopherson <[email protected]> | 2024-12-21 01:16:47 +0000 |
|---|---|---|
| committer | Sean Christopherson <[email protected]> | 2025-01-08 22:08:25 +0000 |
| commit | 4c20cd4cee929aef89118ac8820cefab427c6ae1 (patch) | |
| tree | b5a42f0bf35bf9e7d428a58d0e6c69c7fbc66f32 /net/unix/af_unix.c | |
| parent | KVM: x86: Use LVT_TIMER instead of an open coded literal (diff) | |
| download | kernel-4c20cd4cee929aef89118ac8820cefab427c6ae1.tar.gz kernel-4c20cd4cee929aef89118ac8820cefab427c6ae1.zip | |
KVM: x86: Avoid double RDPKRU when loading host/guest PKRU
Use the raw wrpkru() helper when loading the guest/host's PKRU on switch
to/from guest context, as the write_pkru() wrapper incurs an unnecessary
rdpkru(). In both paths, KVM is guaranteed to have performed RDPKRU since
the last possible write, i.e. KVM has a fresh cache of the current value
in hardware.
This effectively restores KVM's behavior to that of KVM prior to commit
c806e88734b9 ("x86/pkeys: Provide *pkru() helpers"), which renamed the raw
helper from __write_pkru() => wrpkru(), and turned __write_pkru() into a
wrapper. Commit 577ff465f5a6 ("x86/fpu: Only write PKRU if it is different
from current") then added the extra RDPKRU to avoid an unnecessary WRPKRU,
but completely missed that KVM already optimized away pointless writes.
Reported-by: Adrian Hunter <[email protected]>
Fixes: 577ff465f5a6 ("x86/fpu: Only write PKRU if it is different from current")
Signed-off-by: Adrian Hunter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>
Diffstat (limited to 'net/unix/af_unix.c')
0 files changed, 0 insertions, 0 deletions