Re: [PATCH v2 1/6] Add an "info pg" command that prints the current page tables

[Philippe Mathieu-Daudé]

On 31/5/24 16:11, Dr. David Alan Gilbert wrote:
> * Don Porter (porter@cs.unc.edu) wrote:
> > The new "info pg" monitor command prints the current page table,
> > including virtual address ranges, flag bits, and snippets of physical
> > page numbers.  Completely filled regions of the page table with
> > compatible flags are "folded", with the result that the complete
> > output for a freshly booted x86-64 Linux VM can fit in a single
> > terminal window.  The output looks like this:
> >
> > VPN range             Entry         Flags            Physical page
> > [7f0000000-7f0000000] PML4[0fe]     ---DA--UWP
> >    [7f28c0000-7f28fffff]  PDP[0a3]     ---DA--UWP
> >      [7f28c4600-7f28c47ff]  PDE[023]     ---DA--UWP
> >        [7f28c4655-7f28c4656]  PTE[055-056] X--D---U-P 0000007f14-0000007f15
> >        [7f28c465b-7f28c465b]  PTE[05b]     ----A--U-P 0000001cfc
> > ...
> > [ff8000000-ff8000000] PML4[1ff]     ---DA--UWP
> >    [ffff80000-ffffbffff]  PDP[1fe]     ---DA---WP
> >      [ffff81000-ffff81dff]  PDE[008-00e] -GSDA---WP 0000001000-0000001dff
> >    [ffffc0000-fffffffff]  PDP[1ff]     ---DA--UWP
> >      [ffffff400-ffffff5ff]  PDE[1fa]     ---DA--UWP
> >        [ffffff5fb-ffffff5fc]  PTE[1fb-1fc] XG-DACT-WP 00000fec00 00000fee00
> >      [ffffff600-ffffff7ff]  PDE[1fb]     ---DA--UWP
> >        [ffffff600-ffffff600]  PTE[000]     -G-DA--U-P 0000001467
> >
> > This draws heavy inspiration from Austin Clements' original patch.
> >
> > This also adds a generic page table walker, which other monitor
> > and execution commands will be migrated to in subsequent patches.
> >
> > Signed-off-by: Don Porter <porter@cs.unc.edu>
> > ---
> >   hmp-commands-info.hx              |  26 ++
> >   include/monitor/hmp-target.h      |   1 +
> >   target/i386/arch_memory_mapping.c | 486 +++++++++++++++++++++++++++++-
> >   target/i386/cpu.h                 |  16 +
> >   target/i386/monitor.c             | 380 +++++++++++++++++++++++
> >   5 files changed, 908 insertions(+), 1 deletion(-)
> >
> > diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> > index 20a9835ea8..918b82015c 100644
> > --- a/hmp-commands-info.hx
> > +++ b/hmp-commands-info.hx
> > @@ -237,6 +237,32 @@ ERST
> >           .cmd        = hmp_info_mtree,
> >       },
> >   
> > +#if defined(TARGET_I386)

FYI in order to unify all QEMU system binaries as a single
one, we are trying to remove target-specific bits in monitor.

How 'info pg' should work in a binary supporting heterogeneous
emulation?

> > +    {
> > +        .name       = "pg",
> > +        .args_type  = "",
> > +        .params     = "",
> > +        .help       = "show the page table",
> > +        .cmd        = hmp_info_pg,
> > +    },
> > +#endif
>
> So that looks OK