Re: [RFC v2 0/2] target/loongarch: Add loongson binary translation feature

[maobibo]

On 2024/5/27 下午6:39, Philippe Mathieu-Daudé wrote:
Hi Bibo,

On 27/5/24 10:34, Bibo Mao wrote:
Loongson Binary Translation (LBT) is used to accelerate binary
translation. LBT feature is added in kvm mode, not supported in TCG
mode since it is not emulated. And only LBT feature is added here, LBT
registers saving and restoring is not supported since it depeeds on LBT
feautre implemented in KVM kernel

How do you test?
There is a test application using LBT instruction as followings.

If LBT is not enabled, it reports illegal instruction. And it does not 
report error during VM migration.

Regards
Bibo Mao

--------------------------------------------------------------------------
#include <stdio.h>
#include <sched.h>
int main()
{
    int a = 0, b = 0;
    for (;;)
    {
        asm(
            "li.d $t0, 0xff  \n\t"
            ".word ((0x17<<18)|(0x3f<<10)|(1<<5)|0xc) \n\t" // mtflag
            ".word ((0x17<<18)|(0x3f<<10)|(0<<5)|0xc) \n\t" // mfflag
            ".word ((0x17<<18)|(0x3f<<10)|(1<<5)|0xc) \n\t" // mtflag
            "move %0, $t0 \n\t"
            : "=r"(a) : : );
        sched_yield();
        asm(
            ".word ((0x17<<18)|(0x3f<<10)|(0<<5)|0xc) \n\t" // mfflag
            "move %0, $t0 \n\t"
            : "=r"(b) : :);

        if (a != b)
        {
            printf("in: 0x%x <=> out 0x%x \n", a, b);
            return 1;
        }

        sched_yield();
        int top = 0;
        asm(
            ".word (0x8008) \n\t"                 // settm
            ".word ((0x70 << 8) | (5 << 5)) \n\t" // mttop 1
            ".word (0x8009) \n\t"                 // inctop
            : : :);
        sched_yield();
        asm(
            ".word ((0x3a0 << 5) | (0xc)) \n\t" // mfftop
            "move %0, $t0 \n\t"
            : "=r"(top) : : );

        if (top != 6)
        {
            printf("top: %d \n", top);
            return 1;
        }
    }
    return 0;
}


Thanks,

Phil.