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Re: [PATCH 0/5] ARM virt: Add NVDIMM support
From: |
Igor Mammedov |
Subject: |
Re: [PATCH 0/5] ARM virt: Add NVDIMM support |
Date: |
Wed, 11 Dec 2019 08:57:27 +0100 |
On Mon, 9 Dec 2019 17:39:15 +0000
Shameerali Kolothum Thodi <address@hidden> wrote:
> Hi Igor/ xiaoguangrong,
>
> > -----Original Message-----
> > From: Shameerali Kolothum Thodi
> > Sent: 28 November 2019 12:36
> > To: 'Igor Mammedov' <address@hidden>;
> > address@hidden
> > Cc: address@hidden; address@hidden;
> > address@hidden; address@hidden; Linuxarm
> > <address@hidden>; Auger Eric <address@hidden>;
> > address@hidden; xuwei (O) <address@hidden>;
> > address@hidden
> > Subject: RE: [PATCH 0/5] ARM virt: Add NVDIMM support
> >
> >
> >
> > > -----Original Message-----
> > > From: Qemu-devel
> > >
> > [mailto:qemu-devel-bounces+shameerali.kolothum.thodi=huawei.com@nongn
> > > u.org] On Behalf Of Igor Mammedov
> > > Sent: 26 November 2019 08:57
> > > To: Shameerali Kolothum Thodi <address@hidden>
> > > Cc: address@hidden; address@hidden;
> > > address@hidden; address@hidden;
> > > address@hidden; Linuxarm <address@hidden>; Auger Eric
> > > <address@hidden>; address@hidden; xuwei (O)
> > > <address@hidden>; address@hidden
> > > Subject: Re: [PATCH 0/5] ARM virt: Add NVDIMM support
> >
> > [..]
> >
> > > > > 0xb8 Dirty No. -->Another read is attempted
> > > > > > [Qemu]NVDIMM:nvdimm_dsm_func_read_fit: read_fit_out buf size 0x8
> > > > > func_ret_status 3 --> Error status returned
> > > > >
> > > > > status 3 means that QEMU didn't like content of NRAM, and there is
> > > > > only
> > > > > 1 place like this in nvdimm_dsm_func_read_fit()
> > > > > if (read_fit->offset > fit->len) {
> > > > > func_ret_status = NVDIMM_DSM_RET_STATUS_INVALID;
> > > > > goto exit;
> > > > > }
> > > > >
> > > > > so I'd start looking from here and check that QEMU gets expected data
> > > > > in nvdimm_dsm_write(). In other words I'd try to trace/compare
> > > > > content of DSM buffer (from qemu side).
> > > >
> > > > I had printed the DSM buffer previously and it looked same, I will
> > > > double
> > check
> > > > that.
> >
> > Tried printing the buffer in both Qemu/AML code.
> >
> > On Amr64,
>
> [...]
>
> > Attached the SSDT.dsl used for debugging. I am still not clear why on ARM64,
> > 2nd iteration case, the created buffer size in NCAL and RFIT methods have
> > additional 4 bytes!.
> >
> > CreateField (ODAT, Zero, Local1, OBUF)
> > Concatenate (Buffer (Zero){}, OBUF, Local7)
> >
> > Please let me know if you have any clue.
> >
>
> I couldn't figure out yet, why this extra 4 bytes are added by aml code on
> ARM64
> when the nvdimm_dsm_func_read_fit() returns NvdimmFuncReadFITOut without
> any FIT data. ie, when the FIT buffer len (read_len) is zero.
>
> But the below will fix this issue,
>
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index f91eea3802..cddf95f4c1 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -588,7 +588,7 @@ static void nvdimm_dsm_func_read_fit(NVDIMMState *state,
> NvdimmDsmIn *in,
> nvdimm_debug("Read FIT: offset %#x FIT size %#x Dirty %s.\n",
> read_fit->offset, fit->len, fit_buf->dirty ? "Yes" : "No");
>
> - if (read_fit->offset > fit->len) {
> + if (read_fit->offset >= fit->len) {
> func_ret_status = NVDIMM_DSM_RET_STATUS_INVALID;
> goto exit;
> }
>
>
> This will return error code to aml in the second iteration when there is no
> further
> FIT data to report. But, I am not sure why this check was omitted in the
> first place.
>
> Please let me know if this is acceptable and then probably I can look into a
> v2 of this
> series.
Sorry, I don't have capacity to debug this right now,
but I'd prefer if 'why' question was answered first.
Anyways, if something is unclear in how concrete AML code is build/works,
feel free to ask and I'll try to explain and guide you.
> Thanks,
> Shameer
>
>
>