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Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named
From: |
Ben Warren |
Subject: |
Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries |
Date: |
Wed, 25 Jan 2017 09:36:52 -0800 |
Hi Laszlo,
> On Jan 24, 2017, at 7:55 PM, Laszlo Ersek <address@hidden> wrote:
>
> Hi Ben,
>
> sorry about being late to reviewing this series. I hope I can now spend
> more time on it.
>
> - Please do not try to address my comments immediately. It's very
> possible (even likely) that Igor, MST and myself could have different
> opinions on things, so first please await agreement between your reviewers.
>
Thanks for the very detailed review. I’ll give it a couple of days and then
start work on the suggested changes.
> - I think you should have CC'd Igor and Michael directly. I'm adding
> them to this reply; hopefully that will be enough for them to monitor
> this series.
>
> - I'll likely be unable to review everything with 100% coverage; so
> addressing (or sufficiently refuting) my comments might not guarantee
> that the next version will be merged at once.
>
> With all that said:
>
> On 01/25/17 02:43, address@hidden <mailto:address@hidden> wrote:
>> From: Ben Warren <address@hidden <mailto:address@hidden>>
>>
>> This is initially used to patch a 64-bit address into the VM Generation ID
>> SSDT
>
> (1) I think this commit message line is overlong; I think we wrap at 74
> chars or so. Not critical, but worth mentioning.
>
>>
>> Signed-off-by: Ben Warren <address@hidden>
>> ---
>> hw/acpi/aml-build.c | 28 ++++++++++++++++++++++++++++
>> include/hw/acpi/aml-build.h | 4 ++++
>> 2 files changed, 32 insertions(+)
>>
>> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
>> index b2a1e40..dc4edc2 100644
>> --- a/hw/acpi/aml-build.c
>> +++ b/hw/acpi/aml-build.c
>> @@ -285,6 +285,34 @@ build_append_named_dword(GArray *array, const char
>> *name_format, ...)
>> return offset;
>> }
>>
>> +/*
>> + * Build NAME(XXXX, 0x00000000) where 0x00000000 is encoded as a qword,
>> + * and return the offset to 0x00000000 for runtime patching.
>> + *
>> + * Warning: runtime patching is best avoided. Only use this as
>> + * a replacement for DataTableRegion (for guests that don't
>> + * support it).
>> + */
>
> (2) Since we're adding a qword (8-byte integer), the hexadecimal
> constant should have 16 nibbles: 0x0000000000000000. (After copying the
> comment from build_append_named_dword(), it should be actualized.)
>
> (3) Normally the functions in this file that create AML operators carry
> a note about the ACPI spec version and exact location that defines the
> operator. I see that commit f20354910893 ("acpi: add
> build_append_named_dword, returning an offset in buffer", 2016-03-01)
> missed that too.
>
> Unless this tradition has been willfully abandoned, I suggest that you
> add the right reference here, and also (in retrospect) to
> build_append_named_dword().
>
>> +int
>> +build_append_named_qword(GArray *array, const char *name_format, ...)
>> +{
>> + int offset;
>> + va_list ap;
>> +
>> + build_append_byte(array, 0x08); /* NameOp */
>> + va_start(ap, name_format);
>> + build_append_namestringv(array, name_format, ap);
>> + va_end(ap);
>> +
>> + build_append_byte(array, 0x0E); /* QWordPrefix */
>> +
>> + offset = array->len;
>> + build_append_int_noprefix(array, 0x00000000, 8);
>
> (4) I guess the constant should be updated here too, for consistency
> with the comment.
>
> The rest looks okay. (I didn't verify 0x0E == QWordPrefix specifically,
> because an error there would break the functionality immediately, and
> you'd notice.)
>
> Thanks!
> Laszlo
>
>> + assert(array->len == offset + 8);
>> +
>> + return offset;
>> +}
>> +
>> static GPtrArray *alloc_list;
>>
>> static Aml *aml_alloc(void)
>> diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
>> index 559326c..dbf63cf 100644
>> --- a/include/hw/acpi/aml-build.h
>> +++ b/include/hw/acpi/aml-build.h
>> @@ -385,6 +385,10 @@ int
>> build_append_named_dword(GArray *array, const char *name_format, ...)
>> GCC_FMT_ATTR(2, 3);
>>
>> +int
>> +build_append_named_qword(GArray *array, const char *name_format, ...)
>> +GCC_FMT_ATTR(2, 3);
>> +
>> void build_srat_memory(AcpiSratMemoryAffinity *numamem, uint64_t base,
>> uint64_t len, int node, MemoryAffinityFlags flags);
—Ben
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- [Qemu-devel] [PATCH v4 0/9] Add support for VM Generation ID, ben, 2017/01/24
- [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, ben, 2017/01/24
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Laszlo Ersek, 2017/01/24
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Michael S. Tsirkin, 2017/01/26
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Laszlo Ersek, 2017/01/26
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Michael S. Tsirkin, 2017/01/26
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Laszlo Ersek, 2017/01/26
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Michael S. Tsirkin, 2017/01/26
- Re: [Qemu-devel] [PATCH v4 1/9] ACPI: Add a function for building named qword entries, Laszlo Ersek, 2017/01/26