On Wed, Aug 18, 2021, Kees Cook wrote: > On Wed, Aug 18, 2021 at 03:11:28PM +0000, Sean Christopherson wrote: > > From dbdca1f4cd01fee418c252e54c360d518b2b1ad6 Mon Sep 17 00:00:00 2001 > > From: Sean Christopherson <seanjc@xxxxxxxxxx> > > Date: Wed, 18 Aug 2021 08:03:08 -0700 > > Subject: [PATCH] KVM: x86: Replace memset() "optimization" with normal > > per-field writes > > > > Explicitly zero select fields in the emulator's decode cache instead of > > zeroing the fields via a gross memset() that spans six fields. gcc and > > clang are both clever enough to batch the first five fields into a single > > quadword MOV, i.e. memset() and individually zeroing generate identical > > code. > > > > Removing the wart also prepares KVM for FORTIFY_SOURCE performing > > compile-time and run-time field bounds checking for memset(). > > > > No functional change intended. > > > > Reported-by: Kees Cook <keescook@xxxxxxxxxxxx> > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > > Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> > > Do you want me to take this patch into my tree, or do you want to carry > it for KVM directly? That's a Paolo question :-) What's the expected timeframe for landing stricter bounds checking? If it's 5.16 or later, the easiest thing would be to squeak this into 5.15.
