On 20/03/2017 15:56, Peter Maydell wrote:
> On 20 March 2017 at 14:45, Paolo Bonzini <pbonz...@redhat.com> wrote:
>> These commands are useful when testing machine-check passthrough.
>> gpa2hva is useful to inject a MADV_HWPOISON madvise from gdb, while
>> gpa2hpa is useful to inject an error with the mce-inject kernel
>> module.
>>
>> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
>> ---
>> hmp-commands.hx | 32 ++++++++++++++++++
>> monitor.c | 101
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 133 insertions(+)
>>
>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>> index 8819281..0aca984 100644
>> --- a/hmp-commands.hx
>> +++ b/hmp-commands.hx
>> @@ -526,6 +526,38 @@ Dump 80 16 bit values at the start of the video memory.
>> ETEXI
>
> I have some comments which feel kind of nit-picky, but since this
> is a public-facing HMP API I think they need attention since we only
> get one chance to get it right.
>
>> {
>> + .name = "gpa2hva",
>> + .args_type = "addr:l",
>> + .params = "addr",
>> + .help = "print the host virtual address corresponding to a
>> guest physical address",
>> + .cmd = hmp_gpa2hva,
>> + },
>
> How does this work for guest CPUs which have more than one physical
> address space (eg ARM TrustZone)? There's no ability here to specify
> the secure/nonsecure transaction attribute that you need to distinguish
> which kind of guest physical address you're talking about.
>
> The command also doesn't let you specify which CPU you care about,
> which is bad because they don't all have to have the same address map.
It just uses address_space_memory currently. I can make it use the
current CPU address space too, similar to x and xp; it's the same for my
own use.
> The documentation should also say what happens if the guest physaddr
> doesn't correspond to RAM.
An error? :)
>> +#ifdef CONFIG_LINUX
>> + {
>> + .name = "gpa2hpa",
>> + .args_type = "addr:l",
>> + .params = "addr",
>> + .help = "print the host physical address corresponding to a
>> guest physical address",
>> + .cmd = hmp_gpa2hpa,
>> + },
>> +#endif
>> +
>> +STEXI
>> +@item gpa2hpa @var{addr}
>> +@findex gpa2hpa
>> +Print the host physical address at which the guest's physical address
>> @var{addr}
>> +is mapped.
>
> ...what if you're on a system where host RAM exists at multiple host
> physical addresses?
It gives whatever the host OS thinks it's the corresponding host
physical address. It's what happens to be in the page tables for the HVA.
> What if the RAM happens to be paged out?
> (Plus the remarks for gpa2hva apply.)
Another error? :)
Paolo
