Re: [PATCH] kvm-userspace: x86: Support for breakpoints in ROM code

[Avi Kivity <avi@redhat.com>]

Jan Kiszka wrote:
> This is not a hack (it shouldn't have been merged upstream otherwise):
> cpu_physical_memory_write_rom() takes system-wide physical addresses
> while kvm_patch_opcode_byte() works with per-CPU linear addresses.
>   

 From exec.c:

> /* virtual memory access for debug */
> int cpu_memory_rw_debug(CPUState *env, target_ulong addr,
>                         uint8_t *buf, int len, int is_write)
> {
>     int l;
>     target_phys_addr_t phys_addr;
>     target_ulong page;
>
>     while (len > 0) {
>         page = addr & TARGET_PAGE_MASK;
>         phys_addr = cpu_get_phys_page_debug(env, page);
>         /* if no physical page mapped, return an error */
>         if (phys_addr == -1)
>             return -1;
>         l = (page + TARGET_PAGE_SIZE) - addr;
>         if (l > len)
>             l = len;
>         cpu_physical_memory_rw(phys_addr + (addr & ~TARGET_PAGE_MASK),
>                                buf, l, is_write);
>         len -= l;
>         buf += l;
>         addr += l;
>     }
>     return 0;
> }

I'm talking about replacing cpu_physical_memory_rw() with 
cpu_physical_memory_write_rom() (for the write case).  Is there a case 
where the debugger should be prevented from writing into ROM?  If so, 
maybe cpu_memory_rw_debug_rom() for breakpoints?

We shouldn't juggle page descriptors in *kvm*.c.

-- 
error compiling committee.c: too many arguments to function