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Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess proble
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl |
Date: |
Mon, 20 Nov 2017 22:32:29 +0200 |
On Mon, Nov 20, 2017 at 05:55:22PM +0100, Igor Mammedov wrote:
> On Thu, 16 Nov 2017 13:17:02 +0100
> Thomas Huth <address@hidden> wrote:
>
> > The bios-tables-test was writing out files that we pass to iasl in
> > with the wrong endianness in the header when running on a big endian
> > host. So instead of storing mixed endian information in our structures,
> > let's keep everything in little endian and byte-swap it only when we
> > need a value in the code.
> >
> > Reported-by: Daniel P. Berrange <address@hidden>
> > Buglink: https://bugs.launchpad.net/qemu/+bug/1724570
> > Suggested-by: Michael S. Tsirkin <address@hidden>
> > Signed-off-by: Thomas Huth <address@hidden>
> > ---
> > v2: Fixed vmgenid-test which was accidentially broken in v1
> >
> > tests/acpi-utils.h | 27 +++++----------------------
> > tests/bios-tables-test.c | 42 ++++++++++++++++++++++--------------------
> > tests/vmgenid-test.c | 22 ++++++++++++----------
> > 3 files changed, 39 insertions(+), 52 deletions(-)
> >
> > diff --git a/tests/acpi-utils.h b/tests/acpi-utils.h
> > index f8d8723..d5ca5b6 100644
> > --- a/tests/acpi-utils.h
> > +++ b/tests/acpi-utils.h
> > @@ -28,24 +28,9 @@ typedef struct {
> > bool tmp_files_retain; /* do not delete the temp asl/aml */
> > } AcpiSdtTable;
> >
> > -#define ACPI_READ_FIELD(field, addr) \
> > - do { \
> > - switch (sizeof(field)) { \
> > - case 1: \
> > - field = readb(addr); \
> > - break; \
> > - case 2: \
> > - field = readw(addr); \
> > - break; \
> > - case 4: \
> > - field = readl(addr); \
> > - break; \
> > - case 8: \
> > - field = readq(addr); \
> > - break; \
> > - default: \
> > - g_assert(false); \
> > - } \
> probably it's been discussed but, why not do
> leXX_to_cpu()
> here, instead of making each place that access read field
> to do leXX_to_cpu() manually.?
>
> Beside of keeping access to structure in natural host order,
> it should also be less error-prone as field users don't
> have to worry about endianness.
Yes, I suggested that.
The issue is that we don't byte-swap all of the tables
(we can't, that would require a full ACPI parser).
So when byte-swapping we end up with a mixed host/LE
structures.
Keeping it all LE seems cleaner.
--
MST
- [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Thomas Huth, 2017/11/16
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Igor Mammedov, 2017/11/20
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Thomas Huth, 2017/11/20
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Igor Mammedov, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Michael S. Tsirkin, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Igor Mammedov, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Michael S. Tsirkin, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Igor Mammedov, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Michael S. Tsirkin, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Igor Mammedov, 2017/11/21
- Re: [Qemu-devel] [PATCH v2] tests/bios-tables-test: Fix endianess problems when passing data to iasl, Michael S. Tsirkin, 2017/11/21