From: Xiao Guangrong <guangrong.xiao@linux.intel.com> To: Igor Mammedov <imammedo@redhat.com> Cc: pbonzini@redhat.com, gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org Subject: Re: [PATCH v2 1/8] acpi nvdimm: fix wrong buffer size returned by DSM method Date: Wed, 21 Sep 2016 13:30:47 +0800 [thread overview] Message-ID: <56c532d1-f6d0-b64c-3468-4401fa37a0ae@linux.intel.com> (raw) In-Reply-To: <20160920160757.3fdc2ce8@nial.brq.redhat.com> On 09/20/2016 10:07 PM, Igor Mammedov wrote: > On Fri, 12 Aug 2016 14:54:03 +0800 > Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote: > >> Currently, 'RLEN' is the totally buffer size written by QEMU and it is >> ACPI internally used only. The buffer size returned to guest should >> not include 'RLEN' itself > Do you see any errors in guest with this bug present? > It would be nice to put error messages here so that fix could be found > later just by searching git log and qemu-devel for errors user sees > in guest. > No, i did not see any error log in vm. I guess kernel nvdimm driver uses the buffer based on the 'length' field. I will improve the code to check whether the buffer size is matched with this field in vm. > >> >> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> >> --- >> hw/acpi/nvdimm.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c >> index e486128..5454c0f 100644 >> --- a/hw/acpi/nvdimm.c >> +++ b/hw/acpi/nvdimm.c >> @@ -863,6 +863,8 @@ static void nvdimm_build_common_dsm(Aml *dev) >> >> result_size = aml_local(1); >> aml_append(method, aml_store(aml_name("RLEN"), result_size)); >> + /* RLEN is not included in the payload returned to guest. */ >> + aml_append(method, aml_subtract(result_size, aml_int(4), result_size)); > you can merge above store with subtract like this: > aml_subtract(aml_name("RLEN"), foo, result_size) Yes, it is better indeed. > > Style nit: try not to use magic numbers, > look at how RLEN is defined earlier, extract it into macro and reuse in both places Okay. > > >> aml_append(method, aml_store(aml_shiftleft(result_size, aml_int(3)), > instead of shiftleft, I'd suggest use here multiply operator and BITS_PER_BYTE > so it would obvious what's going on and rewrite following without intermediate store. > I agree. However, qemu does not implement multiply primitive, i'd make a separate patchset for these cleanups you suggested. >> result_size)); >> aml_append(method, aml_create_field(aml_name("ODAT"), aml_int(0), > aml_create_field(aml_name("ODAT"), > aml_int(0), > aml_multiply(result_size, aml_int(BITS_PER_BYTE), NULL), > "OBUF")) > > BTW: > dsm_out_buf_size is more descriptive than result_size Yes, indeed. > > also NCAL later uses Arg6 when method has only 5 arguments which doesn't seem right > instead of arg6 you should make/use local variable 'dsm_out_buf' Sorry, my typo. Will fix. > > As sanity check I'd suggest to extract nvdimm ssdt in guest, decompile and compile it back. > Currently I can't compile it back which mean it's really broken. > Good suggestion, i will try it.
WARNING: multiple messages have this Message-ID (diff)
From: Xiao Guangrong <guangrong.xiao@linux.intel.com> To: Igor Mammedov <imammedo@redhat.com> Cc: pbonzini@redhat.com, gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org Subject: Re: [Qemu-devel] [PATCH v2 1/8] acpi nvdimm: fix wrong buffer size returned by DSM method Date: Wed, 21 Sep 2016 13:30:47 +0800 [thread overview] Message-ID: <56c532d1-f6d0-b64c-3468-4401fa37a0ae@linux.intel.com> (raw) In-Reply-To: <20160920160757.3fdc2ce8@nial.brq.redhat.com> On 09/20/2016 10:07 PM, Igor Mammedov wrote: > On Fri, 12 Aug 2016 14:54:03 +0800 > Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote: > >> Currently, 'RLEN' is the totally buffer size written by QEMU and it is >> ACPI internally used only. The buffer size returned to guest should >> not include 'RLEN' itself > Do you see any errors in guest with this bug present? > It would be nice to put error messages here so that fix could be found > later just by searching git log and qemu-devel for errors user sees > in guest. > No, i did not see any error log in vm. I guess kernel nvdimm driver uses the buffer based on the 'length' field. I will improve the code to check whether the buffer size is matched with this field in vm. > >> >> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com> >> --- >> hw/acpi/nvdimm.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c >> index e486128..5454c0f 100644 >> --- a/hw/acpi/nvdimm.c >> +++ b/hw/acpi/nvdimm.c >> @@ -863,6 +863,8 @@ static void nvdimm_build_common_dsm(Aml *dev) >> >> result_size = aml_local(1); >> aml_append(method, aml_store(aml_name("RLEN"), result_size)); >> + /* RLEN is not included in the payload returned to guest. */ >> + aml_append(method, aml_subtract(result_size, aml_int(4), result_size)); > you can merge above store with subtract like this: > aml_subtract(aml_name("RLEN"), foo, result_size) Yes, it is better indeed. > > Style nit: try not to use magic numbers, > look at how RLEN is defined earlier, extract it into macro and reuse in both places Okay. > > >> aml_append(method, aml_store(aml_shiftleft(result_size, aml_int(3)), > instead of shiftleft, I'd suggest use here multiply operator and BITS_PER_BYTE > so it would obvious what's going on and rewrite following without intermediate store. > I agree. However, qemu does not implement multiply primitive, i'd make a separate patchset for these cleanups you suggested. >> result_size)); >> aml_append(method, aml_create_field(aml_name("ODAT"), aml_int(0), > aml_create_field(aml_name("ODAT"), > aml_int(0), > aml_multiply(result_size, aml_int(BITS_PER_BYTE), NULL), > "OBUF")) > > BTW: > dsm_out_buf_size is more descriptive than result_size Yes, indeed. > > also NCAL later uses Arg6 when method has only 5 arguments which doesn't seem right > instead of arg6 you should make/use local variable 'dsm_out_buf' Sorry, my typo. Will fix. > > As sanity check I'd suggest to extract nvdimm ssdt in guest, decompile and compile it back. > Currently I can't compile it back which mean it's really broken. > Good suggestion, i will try it.
next prev parent reply other threads:[~2016-09-21 5:36 UTC|newest] Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-08-12 6:54 [PATCH v2 0/8] nvdimm: hotplug support Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 1/8] acpi nvdimm: fix wrong buffer size returned by DSM method Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-20 14:07 ` Igor Mammedov 2016-09-20 14:07 ` [Qemu-devel] " Igor Mammedov 2016-09-20 15:14 ` Michael S. Tsirkin 2016-09-20 15:14 ` [Qemu-devel] " Michael S. Tsirkin 2016-09-20 16:23 ` Igor Mammedov 2016-09-21 5:30 ` Xiao Guangrong [this message] 2016-09-21 5:30 ` Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 2/8] nvdimm acpi: prebuild nvdimm devices for available slots Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-21 11:48 ` Igor Mammedov 2016-09-21 11:48 ` [Qemu-devel] " Igor Mammedov 2016-09-22 2:43 ` Xiao Guangrong 2016-09-22 2:43 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 3/8] nvdimm acpi: introduce _FIT Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-30 13:14 ` Igor Mammedov 2016-09-30 13:14 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:17 ` Xiao Guangrong 2016-10-08 7:17 ` [Qemu-devel] " Xiao Guangrong 2016-10-10 12:51 ` Igor Mammedov 2016-10-10 12:51 ` [Qemu-devel] " Igor Mammedov 2016-10-10 13:09 ` Xiao Guangrong 2016-10-10 13:09 ` [Qemu-devel] " Xiao Guangrong 2016-10-11 11:49 ` Igor Mammedov 2016-10-11 11:49 ` [Qemu-devel] " Igor Mammedov 2016-10-12 8:20 ` Xiao Guangrong 2016-10-12 8:20 ` [Qemu-devel] " Xiao Guangrong 2016-10-13 13:33 ` Igor Mammedov 2016-10-14 7:43 ` Xiao Guangrong 2016-10-14 11:59 ` Igor Mammedov 2016-08-12 6:54 ` [PATCH v2 4/8] nvdimm acpi: implement Read FIT function Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-30 13:17 ` Igor Mammedov 2016-09-30 13:17 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:17 ` Xiao Guangrong 2016-10-08 7:17 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 5/8] pc-dimm: introduce prepare_unplug() callback Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-10-03 9:45 ` Igor Mammedov 2016-10-03 9:45 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:20 ` Xiao Guangrong 2016-10-08 7:20 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 6/8] pc: memhp: do not export nvdimm's memory via _CRS Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-10-03 13:21 ` Igor Mammedov 2016-10-03 13:21 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:42 ` Xiao Guangrong 2016-10-08 7:42 ` [Qemu-devel] " Xiao Guangrong 2016-10-10 12:47 ` Igor Mammedov 2016-10-10 12:47 ` [Qemu-devel] " Igor Mammedov 2016-10-10 13:10 ` Xiao Guangrong 2016-10-10 13:10 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 7/8] pc: acpi: memhp: nvdimm hotplug support Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 8/8] nvdimm docs: add nvdimm Read FIT function Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-30 14:03 ` Igor Mammedov 2016-09-30 14:03 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:18 ` Xiao Guangrong 2016-10-08 7:18 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 8:35 ` [PATCH v2 0/8] nvdimm: hotplug support Stefan Hajnoczi 2016-08-12 8:35 ` [Qemu-devel] " Stefan Hajnoczi 2016-08-12 15:13 ` Igor Mammedov 2016-08-12 15:13 ` [Qemu-devel] " Igor Mammedov 2016-09-12 7:33 ` Xiao Guangrong 2016-09-12 7:33 ` [Qemu-devel] " Xiao Guangrong 2016-09-12 12:22 ` Igor Mammedov 2016-08-18 17:47 ` Dan Williams 2016-08-18 17:47 ` [Qemu-devel] " Dan Williams 2016-08-18 18:54 ` Vishal Verma 2016-08-18 18:54 ` [Qemu-devel] " Vishal Verma 2016-08-19 3:40 ` Xiao Guangrong 2016-08-19 3:40 ` [Qemu-devel] " Xiao Guangrong 2016-08-19 3:46 ` Xiao Guangrong 2016-08-19 3:46 ` [Qemu-devel] " Xiao Guangrong 2016-08-19 5:14 ` Dan Williams 2016-08-19 5:14 ` [Qemu-devel] " Dan Williams 2016-10-03 13:48 ` Igor Mammedov 2016-10-08 8:34 ` Xiao Guangrong 2016-10-10 12:59 ` Igor Mammedov 2016-10-10 13:57 ` Xiao Guangrong 2016-10-11 12:32 ` Igor Mammedov 2016-10-12 10:19 ` Xiao Guangrong
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