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Re: [Qemu-devel] [PATCH v3 26/32] nvdimm: save arg3 for NVDIMM device _D
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v3 26/32] nvdimm: save arg3 for NVDIMM device _DSM method |
Date: |
Mon, 19 Oct 2015 10:47:05 +0300 |
On Mon, Oct 19, 2015 at 03:14:28PM +0800, Xiao Guangrong wrote:
>
>
> On 10/19/2015 02:50 PM, Michael S. Tsirkin wrote:
> >On Sun, Oct 11, 2015 at 11:52:58AM +0800, Xiao Guangrong wrote:
> >>Check if the input Arg3 is valid then store it into dsm_in if needed
> >>
> >>We only do the save on NVDIMM device since we are not going to support any
> >>function on root device
> >>
> >>Signed-off-by: Xiao Guangrong <address@hidden>
> >>---
> >> hw/mem/nvdimm/acpi.c | 21 ++++++++++++++++++++-
> >> 1 file changed, 20 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/hw/mem/nvdimm/acpi.c b/hw/mem/nvdimm/acpi.c
> >>index d9fa0fd..3b9399c 100644
> >>--- a/hw/mem/nvdimm/acpi.c
> >>+++ b/hw/mem/nvdimm/acpi.c
> >>@@ -442,7 +442,7 @@ static void build_nvdimm_devices(NVDIMMState *state,
> >>GSList *device_list,
> >> int slot = object_property_get_int(OBJECT(nvdimm), DIMM_SLOT_PROP,
> >> NULL);
> >> uint32_t handle = nvdimm_slot_to_handle(slot);
> >>- Aml *dev, *method;
> >>+ Aml *dev, *method, *ifctx;
> >>
> >> dev = aml_device("NV%02X", slot);
> >> aml_append(dev, aml_name_decl("_ADR", aml_int(handle)));
> >>@@ -452,6 +452,24 @@ static void build_nvdimm_devices(NVDIMMState *state,
> >>GSList *device_list,
> >> method = aml_method("_DSM", 4);
> >> {
> >> SAVE_ARG012_HANDLE_LOCK(method, aml_int(handle));
> >>+
> >>+ /* Arg3 is passed as Package and it has one element? */
> >>+ ifctx = aml_if(aml_and(aml_equal(aml_object_type(aml_arg(3)),
> >>+ aml_int(4)),
> >>+ aml_equal(aml_sizeof(aml_arg(3)),
> >
> >aml_arg(3) is used many times below.
> >Pls give it a name that makes sense (not arg3! what is it for?)
> >
>
> Er. aml_arg(3) is just the fourth parameter of _DSM method. Will add some
> comments:
>
> /*
> * The fourth parameter (Arg3) of _DMS is a package which contains a buffer,
> the
> * layout of the buffer is specified by UUID (Arg0), Revision ID (Arg1) and
> * Function Index (Arg2) which are documented in the DSM specification.
> */
>
> >>+ aml_int(1))));
> >
> >Pls document AML constants used.
> >Like this:
> >
> > ifctx = aml_if(aml_and(aml_equal(aml_object_type(aml_arg(3)),
> > aml_int(4 /* 4 - Package */) ),
> > aml_equal(aml_sizeof(aml_arg(3)),
> > aml_int(1))));
> >
> >>+ {
> >>+ /* Local0 = Index(Arg3, 0) */
> >>+ aml_append(ifctx, aml_store(aml_index(aml_arg(3),
> >>aml_int(0)),
> >>+ aml_local(0)));
> >>+ /* Local3 = DeRefOf(Local0) */
> >>+ aml_append(ifctx, aml_store(aml_derefof(aml_local(0)),
> >>+ aml_local(3)));
> >>+ /* ARG3 = Local3 */
> >>+ aml_append(ifctx, aml_store(aml_local(3),
> >>aml_name("ARG3")));
> >
> >This isn't a good way to comment things: you are
> >just adding ASL before the equivalent C.
> >Pls document what's going on.
> >
>
> Okay... i just thought C is little readable than AML. Will change the comment
> to:
>
> /* fetch buffer from the package (Arg3) and store it to DSM memory. */
>
> Thanks.
You can use variables to make the logic clear. E.g.:
Aml *pckg = aml_arg(3);
Aml *pckg_idx = aml_local(0);
Aml *pckg_buf = aml_local(3);
aml_append(ifctx, aml_store(aml_index(pckg, aml_int(0)), pckg_idx);
aml_append(ifctx, aml_store(aml_derefof(pckg_idx), pckg_buf));
This is also better than repeating aml_arg(3) many times.
--
MST
- [Qemu-devel] [PATCH v3 07/32] util: introduce qemu_file_get_page_size(), (continued)
[Qemu-devel] [PATCH v3 20/32] dimm: introduce realize callback, Xiao Guangrong, 2015/10/10
[Qemu-devel] [PATCH v3 28/32] nvdimm: support DSM_CMD_NAMESPACE_LABEL_SIZE function, Xiao Guangrong, 2015/10/10
[Qemu-devel] [PATCH v3 05/32] acpi: add aml_concatenate, Xiao Guangrong, 2015/10/10
[Qemu-devel] [PATCH v3 06/32] acpi: add aml_object_type, Xiao Guangrong, 2015/10/10
[Qemu-devel] [PATCH v3 09/32] exec: allow file_ram_alloc to work on file, Xiao Guangrong, 2015/10/10
[Qemu-devel] [PATCH v3 19/32] dimm: keep the state of the whole backend memory, Xiao Guangrong, 2015/10/10
[Qemu-devel] [PATCH v3 27/32] nvdimm: support DSM_CMD_IMPLEMENTED function, Xiao Guangrong, 2015/10/10