* [kvm-unit-tests PATCH] x86: emulator: Fix h_mem usage in tests_smsw
@ 2014-12-02 22:22 Chris J Arges
2014-12-03 9:15 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Chris J Arges @ 2014-12-02 22:22 UTC (permalink / raw)
To: kvm; +Cc: pbonzini, namit
In emulator.c/tests_smsw, smsw (3) fails because h_mem isn't being set correctly
before smsw is called. By declaring the h_mem function parameter as volatile,
the compiler no longer optimizes out the assignment before smsw.
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
---
x86/emulator.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/x86/emulator.c b/x86/emulator.c
index 5aa4dbf..570628f 100644
--- a/x86/emulator.c
+++ b/x86/emulator.c
@@ -337,7 +337,7 @@ void test_incdecnotneg(void *mem)
report("lock notb", *mb == vb);
}
-void test_smsw(uint64_t *h_mem)
+void test_smsw(volatile uint64_t *h_mem)
{
char mem[16];
unsigned short msw, msw_orig, *pmsw;
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [kvm-unit-tests PATCH] x86: emulator: Fix h_mem usage in tests_smsw
2014-12-02 22:22 [kvm-unit-tests PATCH] x86: emulator: Fix h_mem usage in tests_smsw Chris J Arges
@ 2014-12-03 9:15 ` Paolo Bonzini
2014-12-03 15:44 ` [kvm-unit-tests PATCH v2] " Chris J Arges
0 siblings, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2014-12-03 9:15 UTC (permalink / raw)
To: Chris J Arges, kvm; +Cc: namit
On 02/12/2014 23:22, Chris J Arges wrote:
> In emulator.c/tests_smsw, smsw (3) fails because h_mem isn't being set correctly
> before smsw is called. By declaring the h_mem function parameter as volatile,
> the compiler no longer optimizes out the assignment before smsw.
>
> Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
> ---
> x86/emulator.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/x86/emulator.c b/x86/emulator.c
> index 5aa4dbf..570628f 100644
> --- a/x86/emulator.c
> +++ b/x86/emulator.c
> @@ -337,7 +337,7 @@ void test_incdecnotneg(void *mem)
> report("lock notb", *mb == vb);
> }
>
> -void test_smsw(uint64_t *h_mem)
> +void test_smsw(volatile uint64_t *h_mem)
> {
> char mem[16];
> unsigned short msw, msw_orig, *pmsw;
>
What if you change
asm volatile("smsw %0" : "=m"(*h_mem));
to
asm volatile("smsw %0" : "+m"(*h_mem));
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread* [kvm-unit-tests PATCH v2] x86: emulator: Fix h_mem usage in tests_smsw
2014-12-03 9:15 ` Paolo Bonzini
@ 2014-12-03 15:44 ` Chris J Arges
2014-12-03 15:46 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Chris J Arges @ 2014-12-03 15:44 UTC (permalink / raw)
To: kvm; +Cc: namit, pbonzini, Chris J Arges
In emulator.c/tests_smsw, smsw (3) fails because h_mem isn't being set correctly
before smsw is called. By using the + constraint modifier for memory we can
ensure the compiler no longer optimizes out the assignment before smsw.
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
---
x86/emulator.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/x86/emulator.c b/x86/emulator.c
index 5aa4dbf..1e05574 100644
--- a/x86/emulator.c
+++ b/x86/emulator.c
@@ -359,7 +359,7 @@ void test_smsw(uint64_t *h_mem)
/* Trigger exit on smsw */
*h_mem = 0x12345678abcdeful;
- asm volatile("smsw %0" : "=m"(*h_mem));
+ asm volatile("smsw %0" : "+m"(*h_mem));
report("smsw (3)", msw == (unsigned short)*h_mem &&
(*h_mem & ~0xfffful) == 0x12345678ab0000ul);
}
--
2.1.3
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [kvm-unit-tests PATCH v2] x86: emulator: Fix h_mem usage in tests_smsw
2014-12-03 15:44 ` [kvm-unit-tests PATCH v2] " Chris J Arges
@ 2014-12-03 15:46 ` Paolo Bonzini
0 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2014-12-03 15:46 UTC (permalink / raw)
To: Chris J Arges, kvm; +Cc: namit
On 03/12/2014 16:44, Chris J Arges wrote:
> In emulator.c/tests_smsw, smsw (3) fails because h_mem isn't being set correctly
> before smsw is called. By using the + constraint modifier for memory we can
> ensure the compiler no longer optimizes out the assignment before smsw.
>
> Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
> ---
> x86/emulator.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/x86/emulator.c b/x86/emulator.c
> index 5aa4dbf..1e05574 100644
> --- a/x86/emulator.c
> +++ b/x86/emulator.c
> @@ -359,7 +359,7 @@ void test_smsw(uint64_t *h_mem)
>
> /* Trigger exit on smsw */
> *h_mem = 0x12345678abcdeful;
> - asm volatile("smsw %0" : "=m"(*h_mem));
> + asm volatile("smsw %0" : "+m"(*h_mem));
> report("smsw (3)", msw == (unsigned short)*h_mem &&
> (*h_mem & ~0xfffful) == 0x12345678ab0000ul);
> }
>
Applied, thanks.
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-12-02 22:22 [kvm-unit-tests PATCH] x86: emulator: Fix h_mem usage in tests_smsw Chris J Arges
2014-12-03 9:15 ` Paolo Bonzini
2014-12-03 15:44 ` [kvm-unit-tests PATCH v2] " Chris J Arges
2014-12-03 15:46 ` Paolo Bonzini
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