KVM: selftests: Extend x86's sync_regs_test to check for CR4 races

Browse source

Attempt to modify vcpu->run->s.regs _after_ the sanity checks performed by
KVM_CAP_SYNC_REGS's arch/x86/kvm/x86.c:sync_regs().  This can lead to some
nonsensical vCPU states accompanied by kernel splats, e.g. disabling PAE
while long mode is enabled makes KVM all kinds of confused:

 WARNING: CPU: 0 PID: 1142 at arch/x86/kvm/mmu/paging_tmpl.h:358 paging32_walk_addr_generic+0x431/0x8f0 [kvm]

 arch/x86/kvm/mmu/paging_tmpl.h:
 KVM_BUG_ON(is_long_mode(vcpu) && !is_pae(vcpu), vcpu->kvm)

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Link: https://lore.kernel.org/r/20230728001606.2275586-3-mhal@rbox.co
[sean: see link]
Signed-off-by: Sean Christopherson <seanjc@google.com>

...

This commit is contained in:

Michal Luczaj 2023-07-28 02:12:58 +02:00 • committed by Sean Christopherson

parent 0d033770d4

commit ae895cbe61

1 changed files with 72 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

72

tools/testing/selftests/kvm/x86_64/sync_regs_test.c

View file