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authorShameer Kolothum <shameerali.kolothum.thodi@huawei.com>2020-04-21 13:59:28 +0100
committerMichael S. Tsirkin <mst@redhat.com>2020-05-04 10:25:02 -0400
commit71b0269ae9a80cfd28c3b5946748b92ac8821334 (patch)
treec4f5164229076a6b10db54df2d9189dcef8f7dd0 /hw/acpi/nvdimm.c
parente3a99063af7bc78e51c19cb007acb646d381a9c7 (diff)
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hw/acpi/nvdimm: Fix for NVDIMM incorrect DSM output buffer length
As per ACPI spec 6.3, Table 19-419 Object Conversion Rules, if the Buffer Field <= to the size of an Integer (in bits), it will be treated as an integer. Moreover, the integer size depends on DSDT tables revision number. If revision number is < 2, integer size is 32 bits, otherwise it is 64 bits. Current NVDIMM common DSM aml code (NCAL) uses CreateField() for creating DSM output buffer. This creates an issue in arm/virt platform where DSDT revision number is 2 and results in DSM buffer with a wrong size(8 bytes) gets returned when actual length is < 8 bytes. This causes guest kernel to report, "nfit ACPI0012:00: found a zero length table '0' parsing nfit" In order to fix this, aml code is now modified such that it builds the DSM output buffer in a byte by byte fashion when length is smaller than Integer size. Suggested-by: Igor Mammedov <imammedo@redhat.com> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Reviewed-by: Igor Mammedov <imammedo@redhat.com> Message-Id: <20200421125934.14952-2-shameerali.kolothum.thodi@huawei.com> Acked-by: Peter Maydell <peter.maydell@linaro.org> Tested-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/acpi/nvdimm.c')
-rw-r--r--hw/acpi/nvdimm.c40
1 files changed, 37 insertions, 3 deletions
diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index eb6a37b..df07907 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -938,6 +938,7 @@ static void nvdimm_build_common_dsm(Aml *dev)
Aml *method, *ifctx, *function, *handle, *uuid, *dsm_mem, *elsectx2;
Aml *elsectx, *unsupport, *unpatched, *expected_uuid, *uuid_invalid;
Aml *pckg, *pckg_index, *pckg_buf, *field, *dsm_out_buf, *dsm_out_buf_size;
+ Aml *whilectx, *offset;
uint8_t byte_list[1];
method = aml_method(NVDIMM_COMMON_DSM, 5, AML_SERIALIZED);
@@ -1091,13 +1092,46 @@ static void nvdimm_build_common_dsm(Aml *dev)
/* RLEN is not included in the payload returned to guest. */
aml_append(method, aml_subtract(aml_name(NVDIMM_DSM_OUT_BUF_SIZE),
aml_int(4), dsm_out_buf_size));
+
+ /*
+ * As per ACPI spec 6.3, Table 19-419 Object Conversion Rules, if
+ * the Buffer Field <= to the size of an Integer (in bits), it will
+ * be treated as an integer. Moreover, the integer size depends on
+ * DSDT tables revision number. If revision number is < 2, integer
+ * size is 32 bits, otherwise it is 64 bits.
+ * Because of this CreateField() canot be used if RLEN < Integer Size.
+ *
+ * Also please note that APCI ASL operator SizeOf() doesn't support
+ * Integer and there isn't any other way to figure out the Integer
+ * size. Hence we assume 8 byte as Integer size and if RLEN < 8 bytes,
+ * build dsm_out_buf byte by byte.
+ */
+ ifctx = aml_if(aml_lless(dsm_out_buf_size, aml_int(8)));
+ offset = aml_local(2);
+ aml_append(ifctx, aml_store(aml_int(0), offset));
+ aml_append(ifctx, aml_name_decl("TBUF", aml_buffer(1, NULL)));
+ aml_append(ifctx, aml_store(aml_buffer(0, NULL), dsm_out_buf));
+
+ whilectx = aml_while(aml_lless(offset, dsm_out_buf_size));
+ /* Copy 1 byte at offset from ODAT to temporary buffer(TBUF). */
+ aml_append(whilectx, aml_store(aml_derefof(aml_index(
+ aml_name(NVDIMM_DSM_OUT_BUF), offset)),
+ aml_index(aml_name("TBUF"), aml_int(0))));
+ aml_append(whilectx, aml_concatenate(dsm_out_buf, aml_name("TBUF"),
+ dsm_out_buf));
+ aml_append(whilectx, aml_increment(offset));
+ aml_append(ifctx, whilectx);
+
+ aml_append(ifctx, aml_return(dsm_out_buf));
+ aml_append(method, ifctx);
+
+ /* If RLEN >= Integer size, just use CreateField() operator */
aml_append(method, aml_store(aml_shiftleft(dsm_out_buf_size, aml_int(3)),
dsm_out_buf_size));
aml_append(method, aml_create_field(aml_name(NVDIMM_DSM_OUT_BUF),
aml_int(0), dsm_out_buf_size, "OBUF"));
- aml_append(method, aml_concatenate(aml_buffer(0, NULL), aml_name("OBUF"),
- dsm_out_buf));
- aml_append(method, aml_return(dsm_out_buf));
+ aml_append(method, aml_return(aml_name("OBUF")));
+
aml_append(dev, method);
}