| Message ID | 20220722230241.1944655-5-avagin@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM/x86: add a new hypercall to execute host system | expand |
Andrei Vagin <avagin@google.com> writes: > 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 > Fixes: ac4a4d6de22e ("selftests: kvm: test enforcement of paravirtual cpuid features") > Signed-off-by: Andrei Vagin <avagin@google.com> > --- > 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 ead7011ee8f6..5d85e1c021da 100644 > --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c > +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c > @@ -1422,7 +1422,7 @@ 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)); Wouldn't '"+a"(r)' instead of '"=a"(r)' suffice (assuming we also assing 'r' to 'nr' in the beginning, something like diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index ead7011ee8f6..fdd6554b94a1 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -1418,10 +1418,10 @@ bool set_cpuid(struct kvm_cpuid2 *cpuid, uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2, uint64_t a3) { - uint64_t r; + uint64_t r = nr; asm volatile("vmcall" - : "=a"(r) + : "+a"(r) : "b"(a0), "c"(a1), "d"(a2), "S"(a3)); return r; }
On 8/1/22 13:32, Vitaly Kuznetsov wrote:
> Fixes: ac4a4d6de22e ("selftests: kvm: test enforcement of paravirtual cpuid features")
Queued, thanks.
Paolo
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index ead7011ee8f6..5d85e1c021da 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -1422,7 +1422,7 @@ 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; }
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@google.com> --- tools/testing/selftests/kvm/lib/x86_64/processor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)