On Thu, Jun 06, 2024 at 10:02:48AM -0400, Don Porter 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 <por...@cs.unc.edu>
> ---
> hmp-commands-info.hx | 13 ++
> hw/core/cpu-sysemu.c | 140 ++++++++++++
> include/hw/core/cpu.h | 34 ++-
> include/hw/core/sysemu-cpu-ops.h | 156 +++++++++++++
> include/monitor/hmp-target.h | 1 +
> monitor/hmp-cmds-target.c | 198 +++++++++++++++++
> target/i386/arch_memory_mapping.c | 351 +++++++++++++++++++++++++++++-
> target/i386/cpu.c | 11 +
> target/i386/cpu.h | 15 ++
> target/i386/monitor.c | 165 ++++++++++++++
> 10 files changed, 1082 insertions(+), 2 deletions(-)
> +
> +void hmp_info_pg(Monitor *mon, const QDict *qdict)
> +{
> + struct mem_print_state state;
> +
> + CPUState *cs = mon_get_cpu(mon);
> + if (!cs) {
> + monitor_printf(mon, "Unable to get CPUState. Internal error\n");
> + return;
> + }
> +
> + CPUClass *cc = CPU_GET_CLASS(cs);
> +
> + if ((!cc->sysemu_ops->pte_child)
> + || (!cc->sysemu_ops->pte_leaf)
> + || (!cc->sysemu_ops->pte_leaf_page_size)
> + || (!cc->sysemu_ops->page_table_entries_per_node)
> + || (!cc->sysemu_ops->pte_flags)
> + || (!cc->sysemu_ops->mon_init_page_table_iterator)
> + || (!cc->sysemu_ops->mon_info_pg_print_header)
> + || (!cc->sysemu_ops->mon_flush_page_print_state)) {
> + monitor_printf(mon, "Info pg unsupported on this ISA\n");
> + return;
> + }
> +
> + if (!cc->sysemu_ops->mon_init_page_table_iterator(mon, &state)) {
> + monitor_printf(mon, "Unable to initialize page table iterator\n");
> + return;
> + }
> +
> + state.flush_interior = true;
> + state.require_physical_contiguity = true;
> + state.flusher = cc->sysemu_ops->mon_flush_page_print_state;
> +
> + cc->sysemu_ops->mon_info_pg_print_header(mon, &state);
> +
> + /*
> + * We must visit interior entries to get the hierarchy, but
> + * can skip not present mappings
> + */
> + for_each_pte(cs, &compressing_iterator, &state, true, false);
> +
> + /* Print last entry, if one present */
> + cc->sysemu_ops->mon_flush_page_print_state(cs, &state);
> +}
Please don't add new HMP commands that don't have a QMP
equivalent.
This should be adding an 'x-query-pg' QMP command, which
returns HumanReadableText, and then call that from the HMP
There is guidance on this here:
https://www.qemu.org/docs/master/devel/writing-monitor-commands.html#writing-a-debugging-aid-returning-unstructured-text
If you need more real examples, look at the various
'x-query-XXXX' commands in qapi/machine.json and
their impl.
With regards,
Daniel
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