Additionally HPi is not a mistake, corporate requires that we refer to ourselves as Hewlett Packard Inc since the split in 2015. I will perhaps update
this to be the full name for clarity.
From: McMillan, Erich
Sent: Friday, September 25, 2020 12:15 PM
To: Laszlo Ersek <lersek@redhat.com>; qemu-devel@nongnu.org
Cc: dgilbert@redhat.com; mst@redhat.com; marcel.apfelbaum@gmail.com; imammedo@redhat.com; kraxel@redhat.com
Subject: RE: [PATCH v5] hw/i386/pc: add max combined fw size as machine configuration option
Hi Laszlo,
Thank you for the feedback, apologies that I missed the exact line references I was moving too fast.
I appreciate you taking the time to explain the nuances.
On an unrelated note, it seems that my patches are no longer appearing in
https://lists.nongnu.org/archive/html/qemu-devel/2020-09/index.html is this because I need to cc
qemu-devel@nongnu.org rather than –to?
-Erich
Hi Erich,
when processing review feedback, please pay attention to *where* the
review comments are inserted, in response to your patch email.
I'm pointing this out not because I want to annoy you with my
obsessions, but because I consider this discussion a kind of "git +
mailing lists" training for you. (In accordance with your first message
on the topic.)
Please see specifics below:
On 09/25/20 05:36, Erich Mcmillan wrote:
> From: Erich McMillan <erich.mcmillan@hp.com>
>
> At HPi we have a need for increased fw size to enable testing of our custom fw.
>
> Signed-off-by: Erich McMillan <erich.mcmillan@hp.com>
>
> Change since v4:
> Add explicit return to pc_machine_set_max_fw_size.
> Remove /* default */ from max_fw_size initialization.
> ---
>
> hw/i386/pc.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
> hw/i386/pc_sysfw.c | 13 ++---------
> include/hw/i386/pc.h | 2 ++
> 3 files changed, 56 insertions(+), 11 deletions(-)
Please refer to my earlier feedback, archived at the following location:
8fdbf9f1-5125-1c39-4ec7-f99f017d4345@redhat.com">http://mid.mail-archive.com/8fdbf9f1-5125-1c39-4ec7-f99f017d4345@redhat.com
As I say in that message, the v(n)->v(n+1) changelog belongs 'between
the "---" separator and the diffstat'. In that message, I marked the
specific location with [*].
Basically the "---" separator terminates the commit message, and the
first "diff --git" line starts the code changes. What's between them is
thrown away, when the patch is applied. So in that throwaway area,
git-format-patch places the diffstat automatically (because it gives
reviewers a helpful overview of the patch, but is not useful for patch
application). And that's also the area where the v(n)->v(n+1) changelog
should be included. Traditionally, we place that log above the diffstat.
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index d11daacc23..6e66cbbc41 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1869,6 +1869,51 @@ static void pc_machine_set_max_ram_below_4g(Object *obj, Visitor *v,
> pcms->max_ram_below_4g = value;
> }
>
> +static void pc_machine_get_max_fw_size(Object *obj, Visitor *v,
> + const char *name, void *opaque,
> + Error **errp)
> +{
> + PCMachineState *pcms = PC_MACHINE(obj);
> + uint64_t value = pcms->max_fw_size;
> +
> + visit_type_size(v, name, &value, errp);
> +}
> +
> +static void pc_machine_set_max_fw_size(Object *obj, Visitor *v,
> + const char *name, void *opaque,
> + Error **errp)
> +{
> + PCMachineState *pcms = PC_MACHINE(obj);
> + Error *error = NULL;
> + uint64_t value;
> +
> + visit_type_size(v, name, &value, &error);
> + if (error) {
> + error_propagate(errp, error);
> + return;
> + }
> +
> + /*
> + * We don't have a theoretically justifiable exact lower bound on the base
> + * address of any flash mapping. In practice, the IO-APIC MMIO range is
> + * [0xFEE00000..0xFEE01000] -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
> + * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
> + * size.
> + */
> + if (value > 16 * MiB) {
> + error_setg(errp,
> + "User specified max allowed firmware size %" PRIu64 " is "
> + "greater than 16MiB. If combined firwmare size exceeds "
> + "16MiB the system may not boot, or experience intermittent"
> + "stability issues.",
> + value);
> + }
> +
> + pcms->max_fw_size = value;
> +
> + return;
> +}
This return statement is useless. Please see my review at:
de343c71-f446-c68b-d0bc-5f9db97b5a00@redhat.com">http://mid.mail-archive.com/de343c71-f446-c68b-d0bc-5f9db97b5a00@redhat.com
There I wrote, 'Please put a "return" statement here'. And, my request
was placed *exactly between* the error_setg() call and the closing brace.
The idea being that, if we take the (value > 16 * MiB) branch, then yes
we need to set the error, but we also need to abandon the rest of the
function. If "value" is invalid (out of bounds), then "pcms->max_fw_size
= value" is exactly the assignment that we do *not* want to reach.
> +
> static void pc_machine_initfn(Object *obj)
> {
> PCMachineState *pcms = PC_MACHINE(obj);
> @@ -1884,6 +1929,7 @@ static void pc_machine_initfn(Object *obj)
> pcms->smbus_enabled = true;
> pcms->sata_enabled = true;
> pcms->pit_enabled = true;
> + pcms->max_fw_size = 8 * MiB;
Thank you for dropping the comment.
Summary:
- the changelog is helpful (thanks!), it's placement is not perfect yet
- the return statement should be moved so that it terminate the (value >
16 * MiB) branch.
Also, I think "HPi" (rather than "HP") in the commit message *could* be
a typo (I'm not sure).
Thanks,
Laszlo
>
> pc_system_flash_create(pcms);
> pcms->pcspk = isa_new(TYPE_PC_SPEAKER);
> @@ -2004,6 +2050,12 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
>
> object_class_property_add_bool(oc, PC_MACHINE_PIT,
> pc_machine_get_pit, pc_machine_set_pit);
> +
> + object_class_property_add(oc, PC_MACHINE_MAX_FW_SIZE, "size",
> + pc_machine_get_max_fw_size, pc_machine_set_max_fw_size,
> + NULL, NULL);
> + object_class_property_set_description(oc, PC_MACHINE_MAX_FW_SIZE,
> + "Maximum combined firmware size");
> }
>
> static const TypeInfo pc_machine_info = {
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index b6c0822fe3..22450ba0ef 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -39,15 +39,6 @@
> #include "hw/block/flash.h"
> #include "sysemu/kvm.h"
>
> -/*
> - * We don't have a theoretically justifiable exact lower bound on the base
> - * address of any flash mapping. In practice, the IO-APIC MMIO range is
> - * [0xFEE00000..0xFEE01000] -- see IO_APIC_DEFAULT_ADDRESS --, leaving free
> - * only 18MB-4KB below 4G. For now, restrict the cumulative mapping to 8MB in
> - * size.
> - */
> -#define FLASH_SIZE_LIMIT (8 * MiB)
> -
> #define FLASH_SECTOR_SIZE 4096
>
> static void pc_isa_bios_init(MemoryRegion *rom_memory,
> @@ -182,10 +173,10 @@ static void pc_system_flash_map(PCMachineState *pcms,
> }
> if ((hwaddr)size != size
> || total_size > HWADDR_MAX - size
> - || total_size + size > FLASH_SIZE_LIMIT) {
> + || total_size + size > pcms->max_fw_size) {
> error_report("combined size of system firmware exceeds "
> "%" PRIu64 " bytes",
> - FLASH_SIZE_LIMIT);
> + pcms->max_fw_size);
> exit(1);
> }
>
> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> index fe52e165b2..f7c8e7cbfe 100644
> --- a/include/hw/i386/pc.h
> +++ b/include/hw/i386/pc.h
> @@ -43,6 +43,7 @@ struct PCMachineState {
> bool smbus_enabled;
> bool sata_enabled;
> bool pit_enabled;
> + uint64_t max_fw_size;
>
> /* NUMA information: */
> uint64_t numa_nodes;
> @@ -59,6 +60,7 @@ struct PCMachineState {
> #define PC_MACHINE_SMBUS "smbus"
> #define PC_MACHINE_SATA "sata"
> #define PC_MACHINE_PIT "pit"
> +#define PC_MACHINE_MAX_FW_SIZE "max-fw-size"
>
> /**
> * PCMachineClass:
>