Add a simple _DSM call support for the ACPI0017 device to return fake QTG
ID values of 0 and 1 in all cases. This for _DSM plumbing testing from the OS.
Following edited for readability
Device (CXLM)
{
Name (_HID, "ACPI0017") // _HID: Hardware ID
...
Method (_DSM, 4, Serialized) // _DSM: Device-Specific Method
{
If ((Arg0 == ToUUID ("f365f9a6-a7de-4071-a66a-b40c0b4f8e52")))
{
If ((Arg2 == Zero))
{
Return (Buffer (One) { 0x01 })
}
If ((Arg2 == One))
{
Return (Package (0x02)
{
One,
Package (0x02)
{
Zero,
One
}
})
}
}
}
Signed-off-by: Dave Jiang <dave.ji...@intel.com>
Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
--
v4: Change to package of ints rather than buffers. Also moved to 2 QTG IDs
to improve kernel side testing. Tested on x86 qemu guest against kernel
QTG ID _DSM parsing code to be upstreamed.
v3: Fix output assignment to be BE host friendly. Fix typo in comment.
According to the CXL spec, the DSM output should be 1 WORD to indicate
the max suppoted QTG ID and a package of 0 or more WORDs for the QTG IDs.
In this dummy impementation, we have first WORD with a 1 to indcate max
supprted QTG ID of 1. And second WORD in a package to indicate the QTG
ID of 0.
v2: Minor edit to drop reference to switches in patch description.
Message-Id: <20230904161847.18468-3-jonathan.came...@huawei.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
hw/acpi/cxl.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
hw/i386/acpi-build.c | 1 +
include/hw/acpi/cxl.h | 1 +
3 files changed, 71 insertions(+)
diff --git a/hw/acpi/cxl.c b/hw/acpi/cxl.c
index 92b46bc9323b..9cd7905ea25a 100644
--- a/hw/acpi/cxl.c
+++ b/hw/acpi/cxl.c
@@ -30,6 +30,75 @@
#include "qapi/error.h"
#include "qemu/uuid.h"
+void build_cxl_dsm_method(Aml *dev)
+{
+ Aml *method, *ifctx, *ifctx2;
+
+ method = aml_method("_DSM", 4, AML_SERIALIZED);
+ {
+ Aml *function, *uuid;
+
+ uuid = aml_arg(0);
+ function = aml_arg(2);
+ /* CXL spec v3.0 9.17.3.1 _DSM Function for Retrieving QTG ID */
+ ifctx = aml_if(aml_equal(
+ uuid, aml_touuid("F365F9A6-A7DE-4071-A66A-B40C0B4F8E52")));
+
+ /* Function 0, standard DSM query function */
+ ifctx2 = aml_if(aml_equal(function, aml_int(0)));
+ {
+ uint8_t byte_list[1] = { 0x01 }; /* function 1 only */
+
+ aml_append(ifctx2,
+ aml_return(aml_buffer(sizeof(byte_list), byte_list)));
+ }
+ aml_append(ifctx, ifctx2);
+
+ /*
+ * Function 1
+ * Creating a package with static values. The max supported QTG ID will
+ * be 1 and recommended QTG IDs are 0 and then 1.
+ * The values here are statically created to simplify emulation. Values
+ * from a real BIOS would be determined by the performance of all the
+ * present CXL memory and then assigned.
+ */
+ ifctx2 = aml_if(aml_equal(function, aml_int(1)));
+ {
+ Aml *pak, *pak1;
+
+ /*
+ * Return: A package containing two elements - a WORD that returns
+ * the maximum throttling group that the platform supports, and a
+ * package containing the QTG ID(s) that the platform recommends.
+ * Package {
+ * Max Supported QTG ID
+ * Package {QTG Recommendations}
+ * }
+ *
+ * While the SPEC specified WORD that hints at the value being
+ * 16bit, the ACPI dump of BIOS DSDT table showed that the values
+ * are integers with no specific size specification. aml_int() will
+ * be used for the values.
+ */
+ pak1 = aml_package(2);
+ /* Set QTG ID of 0 */
+ aml_append(pak1, aml_int(0));
+ /* Set QTG ID of 1 */
+ aml_append(pak1, aml_int(1));
+
+ pak = aml_package(2);
+ /* Set Max QTG 1 */
+ aml_append(pak, aml_int(1));
+ aml_append(pak, pak1);
+
+ aml_append(ifctx2, aml_return(pak));
+ }
+ aml_append(ifctx, ifctx2);
+ }
+ aml_append(method, ifctx);
+ aml_append(dev, method);
+}
+
static void cedt_build_chbs(GArray *table_data, PXBCXLDev *cxl)
{
PXBDev *pxb = PXB_DEV(cxl);
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 95199c89008a..692af40b1a75 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1422,6 +1422,7 @@ static void build_acpi0017(Aml *table)
method = aml_method("_STA", 0, AML_NOTSERIALIZED);
aml_append(method, aml_return(aml_int(0x01)));
aml_append(dev, method);
+ build_cxl_dsm_method(dev);
aml_append(scope, dev);
aml_append(table, scope);
diff --git a/include/hw/acpi/cxl.h b/include/hw/acpi/cxl.h
index acf441888683..8f22c71530d8 100644
--- a/include/hw/acpi/cxl.h
+++ b/include/hw/acpi/cxl.h
@@ -25,5 +25,6 @@ void cxl_build_cedt(GArray *table_offsets, GArray *table_data,
BIOSLinker *linker, const char *oem_id,
const char *oem_table_id, CXLState *cxl_state);
void build_cxl_osc_method(Aml *dev);
+void build_cxl_dsm_method(Aml *dev);
#endif
