On Wed, Mar 16, 2022 at 5:27 PM Vishal Verma <vishal.l.verma@xxxxxxxxx> wrote: > > Add full support for negotiating _OSC as defined in the CXL 2.0 spec, as > applicable to CXL-enabled platforms. Advertise support for the CXL > features we support - 'CXL 2.0 port/device register access', 'Protocol > Error Reporting', and 'CL Native Hot Plug'. Request control for 'CXL > Memory Error Reporting'. The requests are dependent on CONFIG_* based > pre-requisites, and prior PCI enabling, similar to how the standard PCI > _OSC bits are determined. Might want to add a clarification here of why this just reflects the PCIe support into the similar CXL fields. For example: The CXL specification does not define any additional constraints on the hotplug flow beyond PCIe native hotplug, so a kernel that supports native PCIe hotplug, supports CXL hotplug. For error handling protocol and link errors just use PCIe AER. There is nascent support for amending AER events with CXL specific status [1], but there's otherwise no additional OS responsibility for CXL errors beyond PCIe AER. CXL Memory Errors behave the same as typical memory errors so CONFIG_MEMORY_FAILURE is sufficient to indicate support to platform firmware. [1]: https://lore.kernel.org/linux-cxl/164740402242.3912056.8303625392871313860.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> > Cc: Robert Moore <robert.moore@xxxxxxxxx> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx> > --- > include/linux/acpi.h | 11 +++ > include/acpi/acpi_bus.h | 6 +- > drivers/acpi/pci_root.c | 147 ++++++++++++++++++++++++++++++++++------ > 3 files changed, 143 insertions(+), 21 deletions(-) > > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index 6274758648e3..1717ccc265d7 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -554,6 +554,8 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context); > #define OSC_QUERY_DWORD 0 /* DWORD 1 */ > #define OSC_SUPPORT_DWORD 1 /* DWORD 2 */ > #define OSC_CONTROL_DWORD 2 /* DWORD 3 */ > +#define OSC_CXL_SUPPORT_DWORD 3 /* DWORD 4 */ > +#define OSC_CXL_CONTROL_DWORD 4 /* DWORD 5 */ > > /* _OSC Capabilities DWORD 1: Query/Control and Error Returns (generic) */ > #define OSC_QUERY_ENABLE 0x00000001 /* input */ > @@ -607,6 +609,15 @@ extern u32 osc_sb_native_usb4_control; > #define OSC_PCI_EXPRESS_LTR_CONTROL 0x00000020 > #define OSC_PCI_EXPRESS_DPC_CONTROL 0x00000080 > > +/* CXL _OSC: Capabilities DWORD 4: Support Field */ > +#define OSC_CXL_1_1_PORT_REG_ACCESS_SUPPORT 0x00000001 > +#define OSC_CXL_2_0_PORT_DEV_REG_ACCESS_SUPPORT 0x00000002 > +#define OSC_CXL_PER_SUPPORT 0x00000004 > +#define OSC_CXL_NATIVE_HP_SUPPORT 0x00000008 > + > +/* CXL _OSC: Capabilities DWORD 5: Control Field */ > +#define OSC_CXL_ERROR_REPORTING_CONTROL 0x00000001 > + > #define ACPI_GSB_ACCESS_ATTRIB_QUICK 0x00000002 > #define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV 0x00000004 > #define ACPI_GSB_ACCESS_ATTRIB_BYTE 0x00000006 > diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h > index 768ef1584055..5776d4c1509a 100644 > --- a/include/acpi/acpi_bus.h > +++ b/include/acpi/acpi_bus.h > @@ -588,8 +588,10 @@ struct acpi_pci_root { > bool cxl_osc_disable; > struct resource secondary; /* downstream bus range */ > > - u32 osc_support_set; /* _OSC state of support bits */ > - u32 osc_control_set; /* _OSC state of control bits */ > + u32 osc_support_set; /* _OSC state of support bits */ > + u32 osc_control_set; /* _OSC state of control bits */ > + u32 cxl_osc_support_set; /* _OSC state of CXL support bits */ > + u32 cxl_osc_control_set; /* _OSC state of CXL control bits */ > phys_addr_t mcfg_addr; > }; > > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > index 2d834504096b..c916318b11a0 100644 > --- a/drivers/acpi/pci_root.c > +++ b/drivers/acpi/pci_root.c > @@ -142,6 +142,17 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = { > { OSC_PCI_EXPRESS_DPC_CONTROL, "DPC" }, > }; > > +static struct pci_osc_bit_struct cxl_osc_support_bit[] = { > + { OSC_CXL_1_1_PORT_REG_ACCESS_SUPPORT, "CXL11PortRegAccess" }, > + { OSC_CXL_2_0_PORT_DEV_REG_ACCESS_SUPPORT, "CXL20PortDevRegAccess" }, > + { OSC_CXL_PER_SUPPORT, "CXLProtocolErrorReporting" }, > + { OSC_CXL_NATIVE_HP_SUPPORT, "CXLNativeHotPlug" }, > +}; > + > +static struct pci_osc_bit_struct cxl_osc_control_bit[] = { > + { OSC_CXL_ERROR_REPORTING_CONTROL, "CXLMemErrorReporting" }, > +}; > + > static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word, > struct pci_osc_bit_struct *table, int size) > { > @@ -170,6 +181,18 @@ static void decode_osc_control(struct acpi_pci_root *root, char *msg, u32 word) > ARRAY_SIZE(pci_osc_control_bit)); > } > > +static void decode_cxl_osc_support(struct acpi_pci_root *root, char *msg, u32 word) > +{ > + decode_osc_bits(root, msg, word, cxl_osc_support_bit, > + ARRAY_SIZE(cxl_osc_support_bit)); > +} > + > +static void decode_cxl_osc_control(struct acpi_pci_root *root, char *msg, u32 word) > +{ > + decode_osc_bits(root, msg, word, cxl_osc_control_bit, > + ARRAY_SIZE(cxl_osc_control_bit)); > +} > + > static bool is_pcie(struct acpi_pci_root *root) > { > return strcmp(acpi_device_hid(root->device), "PNP0A08") == 0; > @@ -199,8 +222,19 @@ static int cap_length(struct acpi_pci_root *root) > return sizeof(u32) * 3; > } > > +static u32 acpi_osc_ctx_get_pci_control(struct acpi_osc_context *context) > +{ > + return *((u32 *)(context->ret.pointer + 8)); > +} > + > +static u32 acpi_osc_ctx_get_cxl_control(struct acpi_osc_context *context) > +{ > + return *((u32 *)(context->ret.pointer + 16)); > +} > + > static acpi_status acpi_pci_run_osc(struct acpi_pci_root *root, > - const u32 *capbuf, u32 *retval) > + const u32 *capbuf, u32 *pci_control, > + u32 *cxl_control) > { > struct acpi_osc_context context = { > .uuid_str = to_uuid(root), > @@ -212,18 +246,20 @@ static acpi_status acpi_pci_run_osc(struct acpi_pci_root *root, > > status = acpi_run_osc(root->device->handle, &context); > if (ACPI_SUCCESS(status)) { > - *retval = *((u32 *)(context.ret.pointer + 8)); > + *pci_control = acpi_osc_ctx_get_pci_control(&context); > + if (is_cxl(root)) > + *cxl_control = acpi_osc_ctx_get_cxl_control(&context); > kfree(context.ret.pointer); > } > return status; > } > > -static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root, > - u32 support, > - u32 *control) > +static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root, u32 support, > + u32 *control, u32 cxl_support, > + u32 *cxl_control) > { > acpi_status status; > - u32 result, capbuf[6]; > + u32 pci_result, cxl_result, capbuf[8]; > > support |= root->osc_support_set; > > @@ -231,11 +267,21 @@ static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root, > capbuf[OSC_SUPPORT_DWORD] = support; > capbuf[OSC_CONTROL_DWORD] = *control | root->osc_control_set; > > + if (is_cxl(root)) { > + cxl_support |= root->cxl_osc_support_set; > + capbuf[OSC_CXL_SUPPORT_DWORD] = cxl_support; > + capbuf[OSC_CXL_CONTROL_DWORD] = *cxl_control | root->cxl_osc_control_set; > + } > + > retry: > - status = acpi_pci_run_osc(root, capbuf, &result); > + status = acpi_pci_run_osc(root, capbuf, &pci_result, &cxl_result); > if (ACPI_SUCCESS(status)) { > root->osc_support_set = support; > - *control = result; > + *control = pci_result; > + if (is_cxl(root)) { > + root->cxl_osc_support_set = cxl_support; > + *cxl_control = cxl_result; > + } > } else if (is_cxl(root)) { > /* > * CXL _OSC is optional on CXL 1.1 hosts. Fall back to PCIe _OSC > @@ -358,6 +404,8 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_dev); > * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex). > * @mask: Mask of _OSC bits to request control of, place to store control mask. > * @support: _OSC supported capability. > + * @cxl_mask: Mask of CXL _OSC control bits, place to store control mask. > + * @cxl_support: CXL _OSC supported capability. > * > * Run _OSC query for @mask and if that is successful, compare the returned > * mask of control bits with @req. If all of the @req bits are set in the > @@ -368,12 +416,14 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_dev); > * _OSC bits the BIOS has granted control of, but its contents are meaningless > * on failure. > **/ > -static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 support) > +static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, > + u32 support, u32 *cxl_mask, > + u32 cxl_support) > { > u32 req = OSC_PCI_EXPRESS_CAPABILITY_CONTROL; > struct acpi_pci_root *root; > acpi_status status; > - u32 ctrl, capbuf[6]; > + u32 ctrl, cxl_ctrl, capbuf[8]; > > if (!mask) > return AE_BAD_PARAMETER; > @@ -385,20 +435,35 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 s > ctrl = *mask; > *mask |= root->osc_control_set; > > + if (is_cxl(root)) { > + cxl_ctrl = *cxl_mask; > + *mask |= root->osc_control_set; > + } > + > /* Need to check the available controls bits before requesting them. */ > do { > - status = acpi_pci_query_osc(root, support, mask); > + status = acpi_pci_query_osc(root, support, mask, cxl_support, > + cxl_mask); > if (ACPI_FAILURE(status)) > return status; > - if (ctrl == *mask) > - break; > - decode_osc_control(root, "platform does not support", > - ctrl & ~(*mask)); > + if (is_cxl(root)) { > + if ((ctrl == *mask) && (cxl_ctrl == *cxl_mask)) > + break; > + decode_cxl_osc_control(root, "platform does not support", > + cxl_ctrl & ~(*cxl_mask)); > + } else { > + if (ctrl == *mask) > + break; > + decode_osc_control(root, "platform does not support", > + ctrl & ~(*mask)); > + } > ctrl = *mask; > - } while (*mask); > + cxl_ctrl = *cxl_mask; > + } while (*mask || *cxl_mask); > > /* No need to request _OSC if the control was already granted. */ > - if ((root->osc_control_set & ctrl) == ctrl) > + if (((root->osc_control_set & ctrl) == ctrl) && > + ((root->cxl_osc_control_set & cxl_ctrl) == cxl_ctrl)) > return AE_OK; > > if ((ctrl & req) != req) { > @@ -410,11 +475,17 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 s > capbuf[OSC_QUERY_DWORD] = 0; > capbuf[OSC_SUPPORT_DWORD] = root->osc_support_set; > capbuf[OSC_CONTROL_DWORD] = ctrl; > - status = acpi_pci_run_osc(root, capbuf, mask); > + if (is_cxl(root)) { > + capbuf[OSC_CXL_SUPPORT_DWORD] = root->cxl_osc_support_set; > + capbuf[OSC_CXL_CONTROL_DWORD] = cxl_ctrl; > + } > + > + status = acpi_pci_run_osc(root, capbuf, mask, cxl_mask); > if (ACPI_FAILURE(status)) > return status; > > root->osc_control_set = *mask; > + root->cxl_osc_control_set = *cxl_mask; > return AE_OK; > } > > @@ -440,6 +511,18 @@ static u32 calculate_support(void) > return support; > } > > +static u32 calculate_cxl_support(void) > +{ > + u32 support; > + > + support = OSC_CXL_2_0_PORT_DEV_REG_ACCESS_SUPPORT; > + support |= OSC_CXL_PER_SUPPORT; I would expect this one to be gated by pci_aer_available() since these errors are reported by PCIe AER. Perhaps also s/PER/PORT_ERROR/? I keep reading PER like 'per' as in 'per-cpu'. > + if (IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)) > + support |= OSC_CXL_NATIVE_HP_SUPPORT; > + > + return support; > +} > + > static u32 calculate_control(void) > { > u32 control; > @@ -471,6 +554,16 @@ static u32 calculate_control(void) > return control; > } > > +static u32 calculate_cxl_control(void) > +{ > + u32 control; > + > + if (pci_aer_available()) > + control |= OSC_CXL_ERROR_REPORTING_CONTROL; In this case the error handling is for memory errors, so this one should be: if (IS_ENABLED(CONFIG_MEMORY_FAILURE)) control |= OSC_CXL_ERROR_REPORTING_CONTROL; ...other than that looks good to me. > + > + return control; > +} > + > static bool os_control_query_checks(struct acpi_pci_root *root, u32 support) > { > struct acpi_device *device = root->device; > @@ -492,6 +585,7 @@ static bool os_control_query_checks(struct acpi_pci_root *root, u32 support) > static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) > { > u32 support, control = 0, requested = 0; > + u32 cxl_support, cxl_control = 0, cxl_requested = 0; > acpi_status status; > struct acpi_device *device = root->device; > acpi_handle handle = device->handle; > @@ -515,10 +609,20 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) > if (os_control_query_checks(root, support)) > requested = control = calculate_control(); > > - status = acpi_pci_osc_control_set(handle, &control, support); > + if (is_cxl(root)) { > + cxl_support = calculate_cxl_support(); > + decode_cxl_osc_support(root, "OS supports", cxl_support); > + cxl_requested = cxl_control = calculate_cxl_control(); > + } > + > + status = acpi_pci_osc_control_set(handle, &control, support, > + &cxl_control, cxl_support); > if (ACPI_SUCCESS(status)) { > if (control) > decode_osc_control(root, "OS now controls", control); > + if (cxl_control) > + decode_cxl_osc_control(root, "OS now controls", > + cxl_control); > > if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) { > /* > @@ -547,6 +651,11 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) > decode_osc_control(root, "OS requested", requested); > decode_osc_control(root, "platform willing to grant", control); > } > + if (cxl_control) { > + decode_cxl_osc_control(root, "OS requested", cxl_requested); > + decode_cxl_osc_control(root, "platform willing to grant", > + cxl_control); > + } > > dev_info(&device->dev, "_OSC: platform retains control of PCIe features (%s)\n", > acpi_format_exception(status)); > -- > 2.35.1 >
