KVM: selftests: Randomly force emulation on x86 writes from guest code
Override vcpu_arch_put_guest() to randomly force emulation on supported accesses. Force emulation of LOCK CMPXCHG as well as a regular MOV to stress KVM's emulation of atomic accesses, which has a unique path in KVM's emulator. Arbitrarily give all the decisions 50/50 odds; absent much, much more sophisticated infrastructure for generating random numbers, it's highly unlikely that doing more than a coin flip with affect selftests' ability to find KVM bugs. This is effectively a regression test for commit 910c57dfa4d1 ("KVM: x86: Mark target gfn of emulated atomic instruction as dirty"). Link: https://lore.kernel.org/r/20240314185459.2439072-6-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
parent
2f2bc6af6a
commit
87aa264cd8
@ -5,6 +5,8 @@
|
||||
#include <stdbool.h>
|
||||
#include <stdint.h>
|
||||
|
||||
#include "test_util.h"
|
||||
|
||||
extern bool is_forced_emulation_enabled;
|
||||
|
||||
struct kvm_vm_arch {
|
||||
@ -22,4 +24,23 @@ static inline bool __vm_arch_has_protected_memory(struct kvm_vm_arch *arch)
|
||||
#define vm_arch_has_protected_memory(vm) \
|
||||
__vm_arch_has_protected_memory(&(vm)->arch)
|
||||
|
||||
#define vcpu_arch_put_guest(mem, __val) \
|
||||
do { \
|
||||
const typeof(mem) val = (__val); \
|
||||
\
|
||||
if (!is_forced_emulation_enabled || guest_random_bool(&guest_rng)) { \
|
||||
(mem) = val; \
|
||||
} else if (guest_random_bool(&guest_rng)) { \
|
||||
__asm__ __volatile__(KVM_FEP "mov %1, %0" \
|
||||
: "+m" (mem) \
|
||||
: "r" (val) : "memory"); \
|
||||
} else { \
|
||||
uint64_t __old = READ_ONCE(mem); \
|
||||
\
|
||||
__asm__ __volatile__(KVM_FEP LOCK_PREFIX "cmpxchg %[new], %[ptr]" \
|
||||
: [ptr] "+m" (mem), [old] "+a" (__old) \
|
||||
: [new]"r" (val) : "memory", "cc"); \
|
||||
} \
|
||||
} while (0)
|
||||
|
||||
#endif // SELFTEST_KVM_UTIL_ARCH_H
|
||||
|
Loading…
x
Reference in New Issue
Block a user