[Qemu-devel] [PATCH 1/1] target/ppc: Fix emulated userspace access to USPRG3

[Qemu-devel] [PATCH 1/1] target/ppc: Fix emulated userspace access to USPRG3

[Sam Bobroff]

On a fully emulated Power8 system, user space is currently unable to
read from USPRG3 (SPR number 0x103) because it receives an illegal
instruction exception.

However the ISA indicates that it should have read access (to the
content of SPR 0x113, similar to some other registers with user space
read-only counterparts).

This patch registers the new SPR for Book 3S processors and has it
provide read-only access to SPR 0x113.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
---
 target/ppc/translate_init.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/target/ppc/translate_init.c b/target/ppc/translate_init.c
index c1a901455c..f863875835 100644
--- a/target/ppc/translate_init.c
+++ b/target/ppc/translate_init.c
@@ -8235,6 +8235,14 @@ static void gen_spr_power8_rpr(CPUPPCState *env)
 #endif
 }
 
+static void gen_spr_book3s_usprg3(CPUPPCState *env)
+{
+    spr_register(env, SPR_USPRG3, "USPRG3",
+                 &spr_read_ureg, SPR_NOACCESS,
+                 &spr_read_ureg, SPR_NOACCESS,
+                 0x00000000);
+}
+
 static void init_proc_book3s_common(CPUPPCState *env)
 {
     gen_spr_ne_601(env);
@@ -8243,6 +8251,7 @@ static void init_proc_book3s_common(CPUPPCState *env)
     gen_spr_book3s_pmu_sup(env);
     gen_spr_book3s_pmu_user(env);
     gen_spr_book3s_ctrl(env);
+    gen_spr_book3s_usprg3(env);
 }
 
 static void init_proc_970(CPUPPCState *env)
-- 
2.12.1.382.gc0f9c7058

Re: [Qemu-devel] [PATCH 1/1] target/ppc: Fix emulated userspace access to USPRG3

[David Gibson]

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On Thu, Apr 20, 2017 at 11:44:17AM +1000, Sam Bobroff wrote:
> On a fully emulated Power8 system, user space is currently unable to
> read from USPRG3 (SPR number 0x103) because it receives an illegal
> instruction exception.
> 
> However the ISA indicates that it should have read access (to the
> content of SPR 0x113, similar to some other registers with user space
> read-only counterparts).
> 
> This patch registers the new SPR for Book 3S processors and has it
> provide read-only access to SPR 0x113.
> 
> Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>

Heh.  I merged a more or less equivalent patch from someone else just
this morning.

> ---
>  target/ppc/translate_init.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/target/ppc/translate_init.c b/target/ppc/translate_init.c
> index c1a901455c..f863875835 100644
> --- a/target/ppc/translate_init.c
> +++ b/target/ppc/translate_init.c
> @@ -8235,6 +8235,14 @@ static void gen_spr_power8_rpr(CPUPPCState *env)
>  #endif
>  }
>  
> +static void gen_spr_book3s_usprg3(CPUPPCState *env)
> +{
> +    spr_register(env, SPR_USPRG3, "USPRG3",
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 &spr_read_ureg, SPR_NOACCESS,
> +                 0x00000000);
> +}
> +
>  static void init_proc_book3s_common(CPUPPCState *env)
>  {
>      gen_spr_ne_601(env);
> @@ -8243,6 +8251,7 @@ static void init_proc_book3s_common(CPUPPCState *env)
>      gen_spr_book3s_pmu_sup(env);
>      gen_spr_book3s_pmu_user(env);
>      gen_spr_book3s_ctrl(env);
> +    gen_spr_book3s_usprg3(env);
>  }
>  
>  static void init_proc_970(CPUPPCState *env)

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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