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[PATCH v2 20/55] accel/tcg: Report unaligned atomics for user-only

Richard Henderson posted 55 patches 4 years, 6 months ago
Maintainers: Cornelia Huck <cohuck@redhat.com>, Greg Kurz <groug@kaod.org>, Bin Meng <bin.meng@windriver.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Paolo Bonzini <pbonzini@redhat.com>, Alistair Francis <alistair.francis@wdc.com>, Eduardo Habkost <ehabkost@redhat.com>, Marek Vasut <marex@denx.de>, Richard Henderson <richard.henderson@linaro.org>, Riku Voipio <riku.voipio@iki.fi>, "Alex Bennée" <alex.bennee@linaro.org>, Thomas Huth <thuth@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Alexandre Iooss <erdnaxe@crans.org>, Stefan Hajnoczi <stefanha@redhat.com>, Jiaxun Yang <jiaxun.yang@flygoat.com>, David Hildenbrand <david@redhat.com>, Palmer Dabbelt <palmer@dabbelt.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Artyom Tarasenko <atar4qemu@gmail.com>, David Gibson <david@gibson.dropbear.id.au>, Aurelien Jarno <aurelien@aurel32.net>, Chris Wulff <crwulff@gmail.com>, Laurent Vivier <laurent@vivier.eu>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, Yoshinori Sato <ysato@users.sourceforge.jp>, Max Filippov <jcmvbkbc@gmail.com>, Mahmoud Mandour <ma.mandourr@gmail.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>
There is a newer version of this series
[PATCH v2 20/55] accel/tcg: Report unaligned atomics for user-only
Posted by Richard Henderson 4 years, 6 months ago 
Use the newly exposed cpu_unaligned_access for atomic_mmu_lookup,
which has access to complete alignment info from the TCGMemOpIdx arg.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/user-exec.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 90d1a2d327..5ad808a25a 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -28,6 +28,7 @@
 #include "qemu/atomic128.h"
 #include "trace/trace-root.h"
 #include "trace/mem.h"
+#include "internal.h"
 
 #undef EAX
 #undef ECX
@@ -1230,11 +1231,22 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
                                TCGMemOpIdx oi, int size, int prot,
                                uintptr_t retaddr)
 {
+    MemOp mop = get_memop(oi);
+    int a_bits = get_alignment_bits(mop);
+    void *ret;
+
+    /* Enforce guest required alignment.  */
+    if (unlikely(addr & ((1 << a_bits) - 1))) {
+        MMUAccessType t = prot == PAGE_READ ? MMU_DATA_LOAD : MMU_DATA_STORE;
+        cpu_unaligned_access(env_cpu(env), addr, t, get_mmuidx(oi), retaddr);
+    }
+
     /* Enforce qemu required alignment.  */
     if (unlikely(addr & (size - 1))) {
         cpu_loop_exit_atomic(env_cpu(env), retaddr);
     }
-    void *ret = g2h(env_cpu(env), addr);
+
+    ret = g2h(env_cpu(env), addr);
     set_helper_retaddr(retaddr);
     return ret;
 }
-- 
2.25.1
Re: [PATCH v2 20/55] accel/tcg: Report unaligned atomics for user-only
Posted by Alex Bennée 4 years, 6 months ago 
Richard Henderson <richard.henderson@linaro.org> writes:

> Use the newly exposed cpu_unaligned_access for atomic_mmu_lookup,
> which has access to complete alignment info from the TCGMemOpIdx arg.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

<snip>
> -    void *ret = g2h(env_cpu(env), addr);
> +
> +    ret = g2h(env_cpu(env), addr);
>      set_helper_retaddr(retaddr);
>      return ret;
>  }


-- 
Alex Bennée
Re: [PATCH v2 20/55] accel/tcg: Report unaligned atomics for user-only
Posted by Philippe Mathieu-Daudé 4 years, 5 months ago 
Hi Richard,

On 8/3/21 6:14 AM, Richard Henderson wrote:
> Use the newly exposed cpu_unaligned_access for atomic_mmu_lookup,
> which has access to complete alignment info from the TCGMemOpIdx arg.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  accel/tcg/user-exec.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
> index 90d1a2d327..5ad808a25a 100644
> --- a/accel/tcg/user-exec.c
> +++ b/accel/tcg/user-exec.c
> @@ -28,6 +28,7 @@
>  #include "qemu/atomic128.h"
>  #include "trace/trace-root.h"
>  #include "trace/mem.h"
> +#include "internal.h"
>  
>  #undef EAX
>  #undef ECX
> @@ -1230,11 +1231,22 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
>                                 TCGMemOpIdx oi, int size, int prot,
>                                 uintptr_t retaddr)
>  {
> +    MemOp mop = get_memop(oi);
> +    int a_bits = get_alignment_bits(mop);
> +    void *ret;
> +
> +    /* Enforce guest required alignment.  */
> +    if (unlikely(addr & ((1 << a_bits) - 1))) {
> +        MMUAccessType t = prot == PAGE_READ ? MMU_DATA_LOAD : MMU_DATA_STORE;
> +        cpu_unaligned_access(env_cpu(env), addr, t, get_mmuidx(oi), retaddr);
> +    }
> +
>      /* Enforce qemu required alignment.  */
>      if (unlikely(addr & (size - 1))) {
>          cpu_loop_exit_atomic(env_cpu(env), retaddr);
>      }
> -    void *ret = g2h(env_cpu(env), addr);
> +
> +    ret = g2h(env_cpu(env), addr);
>      set_helper_retaddr(retaddr);
>      return ret;

Can't we simply do:

       return g2h(env_cpu(env), addr);

?

>  }
>
Re: [PATCH v2 20/55] accel/tcg: Report unaligned atomics for user-only
Posted by Richard Henderson 4 years, 5 months ago 
On 8/17/21 10:51 PM, Philippe Mathieu-Daudé wrote:
>> -    void *ret = g2h(env_cpu(env), addr);
>> +
>> +    ret = g2h(env_cpu(env), addr);
>>       set_helper_retaddr(retaddr);
>>       return ret;
> 
> Can't we simply do:
> 
>         return g2h(env_cpu(env), addr);
> 
> ?

I think the idea was to narrow the range of instructions in which helper_retaddr is set, 
because {set,clear}_helper_retaddr contain barriers.  I didn't give it more thought this 
time around, just kept the ordering.

r~

Patchew 2.1-devel-b67e4c2

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