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author | Vipin Sharma <vipinsh@google.com> | 2022-09-21 23:24:51 -0700 |
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committer | Sean Christopherson <seanjc@google.com> | 2022-09-28 12:47:19 -0700 |
commit | dfb45db43e9f6283a79230c8ea9cb589f14791b0 (patch) | |
tree | 17287a356e4a8301a239b7e1d341c23a03080b4b /mm/mremap.c | |
parent | bf3f11581893494a5fb01eb87b99627edc2a85ff (diff) | |
download | linux-stable-dfb45db43e9f6283a79230c8ea9cb589f14791b0.tar.gz linux-stable-dfb45db43e9f6283a79230c8ea9cb589f14791b0.tar.bz2 linux-stable-dfb45db43e9f6283a79230c8ea9cb589f14791b0.zip |
KVM: selftests: Load RAX with -EFAULT before Hyper-V hypercall
Load RAX with -EFAULT prior to making a Hyper-V hypercall so that tests
can't get false negatives due to the compiler coincidentally loading the
"right" value into RAX, i.e. to ensure that _KVM_ and not the compiler
is correctly clearing RAX on a successful hypercall.
Note, initializing *hv_status (in C code) to -EFAULT is not sufficient
to avoid false negatives, as the compiler can still "clobber" RAX and
thus load garbage into *hv_status if the hypercall faults (or if KVM
doesn't set RAX).
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20220922062451.2927010-1-vipinsh@google.com
[sean: move to separate patch, massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'mm/mremap.c')
0 files changed, 0 insertions, 0 deletions