From: Andrei Vagin <avagin@xxxxxxxxxx> [ Upstream commit 281106f938d3daaea6f8b6723a8217a2a1ef6936 ] kvm_hypercall has to place the hypercall number in rax. Trace events show that kvm_pv_test doesn't work properly: kvm_pv_test-53132: kvm_hypercall: nr 0x0 a0 0x0 a1 0x0 a2 0x0 a3 0x0 kvm_pv_test-53132: kvm_hypercall: nr 0x0 a0 0x0 a1 0x0 a2 0x0 a3 0x0 kvm_pv_test-53132: kvm_hypercall: nr 0x0 a0 0x0 a1 0x0 a2 0x0 a3 0x0 With this change, it starts working as expected: kvm_pv_test-54285: kvm_hypercall: nr 0x5 a0 0x0 a1 0x0 a2 0x0 a3 0x0 kvm_pv_test-54285: kvm_hypercall: nr 0xa a0 0x0 a1 0x0 a2 0x0 a3 0x0 kvm_pv_test-54285: kvm_hypercall: nr 0xb a0 0x0 a1 0x0 a2 0x0 a3 0x0 Signed-off-by: Andrei Vagin <avagin@xxxxxxxxxx> Message-Id: <20220722230241.1944655-5-avagin@xxxxxxxxxx> Fixes: ac4a4d6de22e ("selftests: kvm: test enforcement of paravirtual cpuid features") Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/testing/selftests/kvm/lib/x86_64/processor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index d10c5c05bdf0..f5d2d27bee05 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -1253,6 +1253,6 @@ uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2, asm volatile("vmcall" : "=a"(r) - : "b"(a0), "c"(a1), "d"(a2), "S"(a3)); + : "a"(nr), "b"(a0), "c"(a1), "d"(a2), "S"(a3)); return r; } -- 2.35.1