At 2026-07-11 00:52:35, "Dr. David Alan Gilbert" <[email protected]> wrote:
>* Alano Song ([email protected]) wrote:
>
>
>See below:
>
>> At 2026-07-02 05:05:58, "Dr. David Alan Gilbert" <[email protected]> wrote:
>> >(Added Phil's new address in)
>> >
>> >* [email protected] ([email protected]) wrote:
>> >> When booting an i386 target, the `info tlb` command
>> >> may walk the entire page table hierarchy and emit
>> >> an enormous amount of output.
>> >> It will take dozens of minutes to print all the info,
>> >> because each monitor print function will holds 'mon_lock'.
>> >> This effectively hangs the qemu monitor.
>> >>
>> >> It may be better to add warning note in help message,
>> >> and add a address range by argument to help user control
>> >> the number of output items.
>> >>
>> >> Signed-off-by: Alano Song <[email protected]>
>> >> ---
>> >> hmp-commands-info.hx | 12 ++++---
>> >> target/i386/monitor.c | 82 +++++++++++++++++++++++++++++--------------
>> >> 2 files changed, 64 insertions(+), 30 deletions(-)
>> >>
>> >> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
>> >> index 82134eb6c2..3189e20de3 100644
>> >> --- a/hmp-commands-info.hx
>> >> +++ b/hmp-commands-info.hx
>> >> @@ -188,17 +188,21 @@ ERST
>> >>
>> >> {
>> >> .name = "tlb",
>> >> - .args_type = "",
>> >> - .params = "",
>> >> - .help = "show virtual to physical memory mappings",
>> >> + .args_type = "start:l?,end:l?",
>> >> + .params = "[start [end]]",
>> >> + .help = "show virtual to physical memory mappings. "
>> >
>> >> + "output can be extremely large for i386 target. "
>> >> + "use 'info tlb [start] [end]' to show a range of
>> >> entries.",
>> >
>> >That can be;
>> >> + "The address range can be limited with the
>> >> optional parameters."
>> >
>> >Now, is that the *virtual* address - because it feels like that needs
>> >specifying.
>> >
>> >> .cmd = hmp_info_tlb,
>> >> .arch_bitmask = QEMU_ARCH_I386 | QEMU_ARCH_SH4 | QEMU_ARCH_SPARC
>> >> \
>> >> | QEMU_ARCH_PPC | QEMU_ARCH_XTENSA |
>> >> QEMU_ARCH_M68K,
>> >
>> >You have added the start/end params to the help, but only implemented it on
>> >x86.
>> >That seems odd.
>> >
>> >Dave
>>
>> >
>>
>>
>> Hi Dr. Gilbert,
>>
>> On this patch, I’m currently enabling the `start`/`end` parameters only for
>> x86, since other targets typically maintain a relatively small TLB.
>>
>> For example, xtensa only has a handful of entries, as shown below, so it’s
>> reasonable to simply ignore start/end parameters and dump all items:
>
>We shouldn't blindly ignore parameters; we should always tell the user,
>this is mainly because a user would be very confused if they were using these
>parameters and still getting pages of output from say sparc32.
>
>Perhaps if you create a little helper function that the unsupported
>hmp_info_tlb's can call to check it. Something like
>
>
> if (hmp_check_unsupported_info_tlb_params(qdict,something)) {
> return;
> }
>
>so then it's easy to add that to the ones that's not supported.
>
>> // target/xtensa/cpu.h
>> ...
>> #define MAX_TLB_WAY_SIZE 8
>> ...
>> struct CPUArchState {
>> ...
>> #ifndef CONFIG_USER_ONLY
>> xtensa_tlb_entry itlb[7][MAX_TLB_WAY_SIZE];
>> xtensa_tlb_entry dtlb[10][MAX_TLB_WAY_SIZE];
>> ...
>>
>> The same applies to sparc64, ppc, and sh4.
>>
>>
>> Thanks for the reminder.
>> I went through all architectures supporting the
>>
>> `info tlb` command. I noticed that sparc32 and m68k may also produce a
>> large number of TLB entries, so I plan to extend start/end filtering
>> to those as well.
>> What do you think?
>>
>Yeh that would be great, I think the more important bit is not to confuse
>users about ones which aren't supported.
>
>> >> SRST
>> >> - ``info tlb``
>> >> + ``info tlb`` [*start* [*end*]]
>> >> Show virtual to physical memory mappings.
>> >> + The output can be extremely large for i386 target.
>> >> + Use *start* and *end* to print entries located in address range
>> >> [start, end].
>> >> ERST
>
>I think I'd change it to something like
> *start* and *end can restrict the address range printed to [start, end]
> (This restriction is only supported on i386)
>
>Dave
>
Thanks for your patient review.
I will update the v3 patch as follows:
1. Enable the [start, end] filter for i386/sparc32/m68k target.
Clarify in the helper info that this feature is
limited to the 3 targets above.
2. Add a helper function to emit a warning when the filter is
used on unsupported targets.
3. Refine the helper info about [starg, end] filter.
Alano
>> Alano.
>>
>>
>> >> },
>> >>
>> >> SRST
>> >> - ``info tlb``
>> >> + ``info tlb`` [*start* [*end*]]
>> >> Show virtual to physical memory mappings.
>> >> + The output can be extremely large for i386 target.
>> >> + Use *start* and *end* to print entries located in address range
>> >> [start, end].
>> >> ERST
>> >>
>> >> {
>> >> diff --git a/target/i386/monitor.c b/target/i386/monitor.c
>> >> index a536712c75..c0e0c3e405 100644
>> >> --- a/target/i386/monitor.c
>> >> +++ b/target/i386/monitor.c
>> >> @@ -48,11 +48,9 @@ static hwaddr addr_canonical(CPUArchState *env, hwaddr
>> >> addr)
>> >> return addr;
>> >> }
>> >>
>> >> -static void print_pte(Monitor *mon, CPUArchState *env, hwaddr addr,
>> >> - hwaddr pte, hwaddr mask)
>> >> +static void do_print_pte(Monitor *mon, CPUArchState *env, hwaddr addr,
>> >> + hwaddr pte, hwaddr mask)
>> >> {
>> >> - addr = addr_canonical(env, addr);
>> >> -
>> >> monitor_printf(mon, HWADDR_FMT_plx ": " HWADDR_FMT_plx
>> >> " %c%c%c%c%c%c%c%c%c\n",
>> >> addr,
>> >> @@ -68,7 +66,20 @@ static void print_pte(Monitor *mon, CPUArchState *env,
>> >> hwaddr addr,
>> >> pte & PG_RW_MASK ? 'W' : '-');
>> >> }
>> >>
>> >> -static void tlb_info_32(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as)
>> >> +static void print_pte(Monitor *mon, CPUArchState *env, hwaddr addr,
>> >> + hwaddr pte, hwaddr mask,
>> >> + hwaddr start, hwaddr end)
>> >> +{
>> >> + addr = addr_canonical(env, addr);
>> >> + if (addr < start || addr > end) {
>> >> + return;
>> >> + }
>> >> +
>> >> + do_print_pte(mon, env, addr, pte, mask);
>> >> +}
>> >> +
>> >> +static void tlb_info_32(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as,
>> >> + hwaddr start, hwaddr end)
>> >> {
>> >> const MemTxAttrs attrs = MEMTXATTRS_UNSPECIFIED;
>> >> unsigned int l1, l2;
>> >> @@ -80,15 +91,15 @@ static void tlb_info_32(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as)
>> >> if (pde & PG_PRESENT_MASK) {
>> >> if ((pde & PG_PSE_MASK) && (env->cr[4] & CR4_PSE_MASK)) {
>> >> /* 4M pages */
>> >> - print_pte(mon, env, (l1 << 22), pde, ~((1 << 21) - 1));
>> >> + print_pte(mon, env, (l1 << 22), pde, ~((1 << 21) - 1),
>> >> + start, end);
>> >> } else {
>> >> for(l2 = 0; l2 < 1024; l2++) {
>> >> pte = address_space_ldl_le(as, (pde & ~0xfff) + l2 *
>> >> 4,
>> >> attrs, NULL);
>> >> if (pte & PG_PRESENT_MASK) {
>> >> print_pte(mon, env, (l1 << 22) + (l2 << 12),
>> >> - pte & ~PG_PSE_MASK,
>> >> - ~0xfff);
>> >> + pte & ~PG_PSE_MASK, ~0xfff, start,
>> >> end);
>> >> }
>> >> }
>> >> }
>> >> @@ -96,7 +107,8 @@ static void tlb_info_32(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as)
>> >> }
>> >> }
>> >>
>> >> -static void tlb_info_pae32(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as)
>> >> +static void tlb_info_pae32(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as,
>> >> + hwaddr start, hwaddr end)
>> >> {
>> >> const MemTxAttrs attrs = MEMTXATTRS_UNSPECIFIED;
>> >> unsigned int l1, l2, l3;
>> >> @@ -114,17 +126,19 @@ static void tlb_info_pae32(Monitor *mon,
>> >> CPUArchState *env, AddressSpace *as)
>> >> if (pde & PG_PSE_MASK) {
>> >> /* 2M pages with PAE, CR4.PSE is ignored */
>> >> print_pte(mon, env, (l1 << 30) + (l2 << 21), pde,
>> >> - ~((hwaddr)(1 << 20) - 1));
>> >> + ~((hwaddr)(1 << 20) - 1),
>> >> + start, end);
>> >> } else {
>> >> pt_addr = pde & 0x3fffffffff000ULL;
>> >> for (l3 = 0; l3 < 512; l3++) {
>> >> pte = address_space_ldq_le(as, pt_addr + l3
>> >> * 8,
>> >> attrs, NULL);
>> >> if (pte & PG_PRESENT_MASK) {
>> >> - print_pte(mon, env, (l1 << 30) + (l2 <<
>> >> 21)
>> >> - + (l3 << 12),
>> >> + print_pte(mon, env,
>> >> + (l1 << 30) + (l2 << 21) + (l3
>> >> << 12),
>> >> pte & ~PG_PSE_MASK,
>> >> - ~(hwaddr)0xfff);
>> >> + ~(hwaddr)0xfff,
>> >> + start, end);
>> >> }
>> >> }
>> >> }
>> >> @@ -136,7 +150,8 @@ static void tlb_info_pae32(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as)
>> >>
>> >> #ifdef TARGET_X86_64
>> >> static void tlb_info_la48(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as,
>> >> - uint64_t l0, uint64_t pml4_addr)
>> >> + uint64_t l0, uint64_t pml4_addr, hwaddr start,
>> >> + hwaddr end)
>> >> {
>> >> const MemTxAttrs attrs = MEMTXATTRS_UNSPECIFIED;
>> >> uint64_t l1, l2, l3, l4;
>> >> @@ -159,7 +174,7 @@ static void tlb_info_la48(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as,
>> >> if (pdpe & PG_PSE_MASK) {
>> >> /* 1G pages, CR4.PSE is ignored */
>> >> print_pte(mon, env, (l0 << 48) + (l1 << 39) + (l2 << 30),
>> >> - pdpe, 0x3ffffc0000000ULL);
>> >> + pdpe, 0x3ffffc0000000ULL, start, end);
>> >> continue;
>> >> }
>> >>
>> >> @@ -172,8 +187,9 @@ static void tlb_info_la48(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as,
>> >>
>> >> if (pde & PG_PSE_MASK) {
>> >> /* 2M pages, CR4.PSE is ignored */
>> >> - print_pte(mon, env, (l0 << 48) + (l1 << 39) + (l2 <<
>> >> 30) +
>> >> - (l3 << 21), pde, 0x3ffffffe00000ULL);
>> >> + print_pte(mon, env,
>> >> + (l0 << 48) + (l1 << 39) + (l2 << 30) + (l3
>> >> << 21),
>> >> + pde, 0x3ffffffe00000ULL, start, end);
>> >> continue;
>> >> }
>> >>
>> >> @@ -182,9 +198,11 @@ static void tlb_info_la48(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as,
>> >> pte = address_space_ldq_le(as, pt_addr + l4 * 8,
>> >> attrs, NULL);
>> >> if (pte & PG_PRESENT_MASK) {
>> >> - print_pte(mon, env, (l0 << 48) + (l1 << 39) +
>> >> - (l2 << 30) + (l3 << 21) + (l4 << 12),
>> >> - pte & ~PG_PSE_MASK, 0x3fffffffff000ULL);
>> >> + print_pte(mon, env,
>> >> + (l0 << 48) + (l1 << 39) + (l2 << 30) +
>> >> + (l3 << 21) + (l4 << 12),
>> >> + pte & ~PG_PSE_MASK,
>> >> + 0x3fffffffff000ULL, start, end);
>> >> }
>> >> }
>> >> }
>> >> @@ -192,7 +210,8 @@ static void tlb_info_la48(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as,
>> >> }
>> >> }
>> >>
>> >> -static void tlb_info_la57(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as)
>> >> +static void tlb_info_la57(Monitor *mon, CPUArchState *env, AddressSpace
>> >> *as,
>> >> + hwaddr start, hwaddr end)
>> >> {
>> >> const MemTxAttrs attrs = MEMTXATTRS_UNSPECIFIED;
>> >> uint64_t l0;
>> >> @@ -203,7 +222,8 @@ static void tlb_info_la57(Monitor *mon, CPUArchState
>> >> *env, AddressSpace *as)
>> >> for (l0 = 0; l0 < 512; l0++) {
>> >> pml5e = address_space_ldq_le(as, pml5_addr + l0 * 8, attrs,
>> >> NULL);
>> >> if (pml5e & PG_PRESENT_MASK) {
>> >> - tlb_info_la48(mon, env, as, l0, pml5e & 0x3fffffffff000ULL);
>> >> + tlb_info_la48(mon, env, as, l0, pml5e & 0x3fffffffff000ULL,
>> >> + start, end);
>> >> }
>> >> }
>> >> }
>> >> @@ -213,6 +233,14 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
>> >> {
>> >> CPUArchState *env;
>> >> AddressSpace *as;
>> >> + hwaddr start = 0, end = HWADDR_MAX;
>> >> +
>> >> + if (qdict_haskey(qdict, "start")) {
>> >> + start = (hwaddr)qdict_get_int(qdict, "start");
>> >> + }
>> >> + if (qdict_haskey(qdict, "end")) {
>> >> + end = (hwaddr)qdict_get_int(qdict, "end");
>> >> + }
>> >>
>> >> env = mon_get_cpu_env(mon);
>> >> if (!env) {
>> >> @@ -229,17 +257,19 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
>> >> #ifdef TARGET_X86_64
>> >> if (env->hflags & HF_LMA_MASK) {
>> >> if (env->cr[4] & CR4_LA57_MASK) {
>> >> - tlb_info_la57(mon, env, as);
>> >> + tlb_info_la57(mon, env, as, start, end);
>> >> } else {
>> >> - tlb_info_la48(mon, env, as, 0, env->cr[3] &
>> >> 0x3fffffffff000ULL);
>> >> + tlb_info_la48(mon, env, as, 0,
>> >> + env->cr[3] & 0x3fffffffff000ULL,
>> >> + start, end);
>> >> }
>> >> } else
>> >> #endif
>> >> {
>> >> - tlb_info_pae32(mon, env, as);
>> >> + tlb_info_pae32(mon, env, as, start, end);
>> >> }
>> >> } else {
>> >> - tlb_info_32(mon, env, as);
>> >> + tlb_info_32(mon, env, as, start, end);
>> >> }
>> >> }
>> >>
>> >> --
>> >> 2.43.0
>> >>
>> >--
>> > -----Open up your eyes, open up your mind, open up your code -------
>> >/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
>> >\ dave @ treblig.org | | In Hex /
>> > \ _________________________|_____ http://www.treblig.org |_______/
>--
> -----Open up your eyes, open up your mind, open up your code -------
>/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
>\ dave @ treblig.org | | In Hex /
> \ _________________________|_____ http://www.treblig.org |_______/
