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Re: [Qemu-devel] [PATCH v1] hw: fix error reporting for missing option R
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH v1] hw: fix error reporting for missing option ROMs |
Date: |
Fri, 11 Mar 2016 09:27:44 +0000 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Thu, Mar 10, 2016 at 01:25:08PM -0700, Eric Blake wrote:
> On 03/10/2016 10:28 AM, Daniel P. Berrange wrote:
> > If QEMU fails to load any of the VGA ROMs, it prints a message
> > to stderr and then carries on as if everything was fine, despite
> > the VGA interface not being functional. This extends the the
> > rom_add_file() method to accept a 'Error **errp' parameter. The
> > VGA device realizefn() impls can now pass in the errp they already
> > have and get errors reported as fatal problems.
> >
> > Signed-off-by: Daniel P. Berrange <address@hidden>
> > ---
> > hw/core/loader.c | 40 +++++++++++++++++++++++++---------------
> > hw/display/cirrus_vga.c | 4 +++-
> > hw/display/vga-isa.c | 4 +++-
> > hw/i386/pc.c | 4 ++--
> > hw/i386/pc_sysfw.c | 2 +-
> > hw/misc/sga.c | 4 +++-
> > hw/pci/pci.c | 8 ++++++--
> > include/hw/loader.h | 16 +++++++++-------
> > 8 files changed, 52 insertions(+), 30 deletions(-)
> >
> > diff --git a/hw/core/loader.c b/hw/core/loader.c
> > index 8e8031c..010e442 100644
> > --- a/hw/core/loader.c
> > +++ b/hw/core/loader.c
> > @@ -142,7 +142,7 @@ int load_image_targphys(const char *filename,
> > return -1;
> > }
> > if (size > 0) {
> > - rom_add_file_fixed(filename, addr, -1);
> > + rom_add_file_fixed(filename, addr, -1, NULL);
> > }
>
> Why is this one ignoring the error? Would &error_abort be better if we
> know it can't fail?
The loader.h header file has a tonne of different APIs which load files.
int get_image_size(const char *filename);
int load_image(const char *filename, uint8_t *addr); /* deprecated */
ssize_t load_image_size(const char *filename, void *addr, size_t size);
int load_image_targphys(const char *filename, hwaddr,
uint64_t max_sz);
int load_image_mr(const char *filename, MemoryRegion *mr);
int load_image_gzipped_buffer(const char *filename, uint64_t max_sz,
uint8_t **buffer);
int load_image_gzipped(const char *filename, hwaddr addr, uint64_t max_sz);
void load_elf_hdr(const char *filename, void *hdr, bool *is64, Error **errp);
int load_aout(const char *filename, hwaddr addr, int max_sz,
int bswap_needed, hwaddr target_page_size);
int load_uimage(const char *filename, hwaddr *ep,
hwaddr *loadaddr, int *is_linux,
uint64_t (*translate_fn)(void *, uint64_t),
void *translate_opaque);
int load_ramdisk(const char *filename, hwaddr addr, uint64_t max_sz);
If I change all those to add an Error **errp, the ripple effect across the
rest of QEMU is pretty huge. So I decided it would be better to incrementally
convert stuff, starting with the rom_add_* functions first. Converting more
of the load_* functions can be a separate followup patch, since this one does
not make the situation worse for those.
> > @@ -162,7 +162,7 @@ int load_image_mr(const char *filename, MemoryRegion
> > *mr)
> > return -1;
> > }
> > if (size > 0) {
> > - if (rom_add_file_mr(filename, mr, -1) < 0) {
> > + if (rom_add_file_mr(filename, mr, -1, NULL) < 0) {
> > return -1;
>
> This one still detects and passes on failure, but loses the error
> message. I guess that's okay, as long as this patch is incrementally
> better somewhere else.
See previous explanation.
> > @@ -847,8 +849,9 @@ int rom_add_file(const char *file, const char *fw_dir,
> >
> > fd = open(rom->path, O_RDONLY | O_BINARY);
> > if (fd == -1) {
> > - fprintf(stderr, "Could not open option rom '%s': %s\n",
> > - rom->path, strerror(errno));
> > + error_setg_errno(errp, errno,
> > + "Could not open option rom '%s'",
> > + rom->path);
>
> would error_setg_file_open() be any better here, for consistency?
Sure.
>
> > +++ b/hw/i386/pc.c
> > @@ -1264,7 +1264,7 @@ void xen_load_linux(PCMachineState *pcms)
> > for (i = 0; i < nb_option_roms; i++) {
> > assert(!strcmp(option_rom[i].name, "linuxboot.bin") ||
> > !strcmp(option_rom[i].name, "multiboot.bin"));
> > - rom_add_option(option_rom[i].name, option_rom[i].bootindex);
> > + rom_add_option(option_rom[i].name, option_rom[i].bootindex, NULL);
>
> Another place that blindly ignores things; should we use &error_abort?
The xen_load_linux() function doesn't have any Error **Errp to propagate
the errors back up, so I left that unset. I guess error_abort is a valid
alternative, since this is in startup path, not hotplug.
> > +++ b/hw/i386/pc_sysfw.c
> > @@ -199,7 +199,7 @@ static void old_pc_system_rom_init(MemoryRegion
> > *rom_memory, bool isapc_ram_fw)
> > if (!isapc_ram_fw) {
> > memory_region_set_readonly(bios, true);
> > }
> > - ret = rom_add_file_fixed(bios_name, (uint32_t)(-bios_size), -1);
> > + ret = rom_add_file_fixed(bios_name, (uint32_t)(-bios_size), -1, NULL);
> > if (ret != 0) {
> > bios_error:
> > fprintf(stderr, "qemu: could not load PC BIOS '%s'\n", bios_name);
>
> This one makes sense - you are incrementally improving the interface,
> and not all callers; this caller was already reporting errors and could
> be cleaned up in a later commit to use &err instead of fprintf().
Regards,
Daniel
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