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Re: [PATCH] softmmu/vl.c: fix too slow TCG regression
From: |
Alex Bennée |
Subject: |
Re: [PATCH] softmmu/vl.c: fix too slow TCG regression |
Date: |
Wed, 26 Feb 2020 18:21:05 +0000 |
User-agent: |
mu4e 1.3.8; emacs 27.0.60 |
Igor Mammedov <address@hidden> writes:
> Commit a1b18df9a4 moved -m option parsing after configure_accelerators()
> that broke TCG accelerator initialization which accesses global ram_size
> from size_code_gen_buffer() which is equal to 0 at that moment.
>
> Partially revert a1b18df9a4, by returning set_memory_options() to its
> original location and only keep 32-bit host VA check and 'memory-backend'
> size check introduced by fe64d06afc at current place.
>
> Signed-off-by: Igor Mammedov <address@hidden>
> ---
>
> PS:
> This should take care of regression and give more time to think about
> how to remove size_code_gen_buffer() dependency on ram_size
Tested-by: Alex Bennée <address@hidden>
FWIW I don't think it will take too long to fixup size_code_gen_buffer.
See:
Subject: [PATCH v1 0/4] Fix codegen translation cache size
Date: Wed, 26 Feb 2020 18:10:16 +0000
Message-Id: <address@hidden>
> ---
> softmmu/vl.c | 49 +++++++++++++++++++++++++------------------------
> 1 file changed, 25 insertions(+), 24 deletions(-)
>
> diff --git a/softmmu/vl.c b/softmmu/vl.c
> index a9cce78f45..da7577129c 100644
> --- a/softmmu/vl.c
> +++ b/softmmu/vl.c
> @@ -2634,29 +2634,6 @@ static void set_memory_options(uint64_t *ram_slots,
> ram_addr_t *maxram_size,
> exit(EXIT_FAILURE);
> }
>
> - if (current_machine->ram_memdev_id) {
> - Object *backend;
> - ram_addr_t backend_size;
> -
> - backend = object_resolve_path_type(current_machine->ram_memdev_id,
> - TYPE_MEMORY_BACKEND, NULL);
> - backend_size = object_property_get_uint(backend, "size",
> &error_abort);
> - if (mem_str && backend_size != ram_size) {
> - error_report("Size specified by -m option must match size of
> "
> - "explicitly specified 'memory-backend'
> property");
> - exit(EXIT_FAILURE);
> - }
> - ram_size = backend_size;
> - }
> -
> - if (!xen_enabled()) {
> - /* On 32-bit hosts, QEMU is limited by virtual address space */
> - if (ram_size > (2047 << 20) && HOST_LONG_BITS == 32) {
> - error_report("at most 2047 MB RAM can be simulated");
> - exit(1);
> - }
> - }
> -
> loc_pop(&loc);
> }
>
> @@ -3821,6 +3798,8 @@ void qemu_init(int argc, char **argv, char **envp)
> machine_class = select_machine();
> object_set_machine_compat_props(machine_class->compat_props);
>
> + set_memory_options(&ram_slots, &maxram_size, machine_class);
> +
> os_daemonize();
>
> /*
> @@ -4296,7 +4275,29 @@ void qemu_init(int argc, char **argv, char **envp)
> current_machine->cpu_type = parse_cpu_option(cpu_option);
> }
>
> - set_memory_options(&ram_slots, &maxram_size, machine_class);
> + if (!xen_enabled()) {
> + /* On 32-bit hosts, QEMU is limited by virtual address space */
> + if (ram_size > (2047 << 20) && HOST_LONG_BITS == 32) {
> + error_report("at most 2047 MB RAM can be simulated");
> + exit(1);
> + }
> + }
> +
> + if (current_machine->ram_memdev_id) {
> + Object *backend;
> + ram_addr_t backend_size;
> +
> + backend = object_resolve_path_type(current_machine->ram_memdev_id,
> + TYPE_MEMORY_BACKEND, NULL);
> + backend_size = object_property_get_uint(backend, "size",
> &error_abort);
> + if (backend_size != ram_size) {
> + error_report("Size specified by -m option must match size of
> "
> + "explicitly specified 'memory-backend'
> property");
> + exit(EXIT_FAILURE);
> + }
> + ram_size = backend_size;
> + }
> +
> current_machine->ram_size = ram_size;
> current_machine->maxram_size = maxram_size;
> current_machine->ram_slots = ram_slots;
--
Alex Bennée