The existence of CF_PCREL can improve performance with the guest
kernel's address space randomization.  Each guest process maps
libc.so (et al) at a different virtual address, and this allows
those translations to be shared.

Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
---
 target/riscv/cpu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 646fa31a59..3b562d5d9f 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -1193,6 +1193,8 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
 
 
 #ifndef CONFIG_USER_ONLY
+    cs->tcg_cflags |= CF_PCREL;
+
     if (cpu->cfg.ext_sstc) {
         riscv_timer_init(cpu);
     }
-- 
2.25.1

On 2023/3/31 9:45, Weiwei Li wrote:
> The existence of CF_PCREL can improve performance with the guest
> kernel's address space randomization.  Each guest process maps
> libc.so (et al) at a different virtual address, and this allows
> those translations to be shared.
>
> Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
> Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
> ---
>   target/riscv/cpu.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 646fa31a59..3b562d5d9f 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -1193,6 +1193,8 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
>   
>   
>   #ifndef CONFIG_USER_ONLY
> +    cs->tcg_cflags |= CF_PCREL;
> +

Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>

Zhiwei

>       if (cpu->cfg.ext_sstc) {
>           riscv_timer_init(cpu);
>       }