On 12/16/25 8:44 AM, Lazar, Lijo wrote:
On 16-Dec-25 7:38 PM, Mario Limonciello wrote:On 12/16/25 3:43 AM, Lazar, Lijo wrote:On 12-Dec-25 1:29 PM, Yo-Jung Leo Lin (AMD) wrote:Add a uma/ directory containing two sysfs files as interfaces to inspect or change UMA carveout size. These files are: - uma/carveout_options: a read-only file listing all the available UMA allocation options and their index. - uma/carveout: a file that is both readable and writable. On read, it shows the index of the current setting. Writing a valid index into this file allows users to change the UMA carveout size to that option on the next boot. Co-developed-by: Mario Limonciello (AMD) <[email protected]> Signed-off-by: Mario Limonciello (AMD) <[email protected]> Reviewed-by: Alex Deucher <[email protected]> Signed-off-by: Yo-Jung Leo Lin (AMD) <[email protected]> ---drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 143 +++++++++++++++++ + + ++++++++++1 file changed, 143 insertions(+)diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/ gpu/ drm/amd/amdgpu/amdgpu_device.cindex 903c4706040d..e78e6982312c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c @@ -36,6 +36,7 @@ #include <linux/pci.h> #include <linux/pci-p2pdma.h> #include <linux/apple-gmux.h> +#include <linux/nospec.h> #include <drm/drm_atomic_helper.h> #include <drm/drm_client_event.h>@@ -417,6 +418,146 @@ static const struct attribute_group amdgpu_board_attrs_group = {.is_visible = amdgpu_board_attrs_is_visible }; +static ssize_t carveout_options_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct drm_device *ddev = dev_get_drvdata(dev); + struct amdgpu_device *adev = drm_to_adev(ddev); + struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info; + uint32_t memory_carved; + ssize_t size = 0; + + if (!uma_info || !uma_info->num_entries) + return -ENODEV; + + for (int i = 0; i < uma_info->num_entries; i++) { + memory_carved = uma_info->entries[i].memory_carved_mb; + if (memory_carved >= SZ_1G/SZ_1M) { + size += sysfs_emit_at(buf, size, "%d: %s (%u GB)\n", + i, + uma_info->entries[i].name, + memory_carved >> 10); + } else { + size += sysfs_emit_at(buf, size, "%d: %s (%u MB)\n", + i, + uma_info->entries[i].name, + memory_carved); + } + } + + return size; +} +static DEVICE_ATTR_RO(carveout_options); + +static ssize_t carveout_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct drm_device *ddev = dev_get_drvdata(dev); + struct amdgpu_device *adev = drm_to_adev(ddev); + + return sysfs_emit(buf, "%u\n", adev->uma_info.uma_option_index);It would be better to show the size along with the index.This idea complicates userspace parsing because rather than a atoi() parser you now need to do sscanf().IE - I like it the way it is in the series at the moment.Userspace already has to go through this for carveout_options parsing. It does not make any difference :)
Oh I guess you're right, userspace wouldn't just present a string from carveout options, it would need to know what index went with what string which means parsing to populate a UI (for example).
I was thinking of an easier way without cross reference. It would be better even if you put the actual carve out size instead of an index (assuming carve out size is deterministic).Thanks, LijoRegardless, series is - Reviewed-by: Lijo Lazar <[email protected]> Thanks, Lijo+} + +static ssize_t carveout_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct drm_device *ddev = dev_get_drvdata(dev); + struct amdgpu_device *adev = drm_to_adev(ddev); + struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info; + struct amdgpu_uma_carveout_option *opt; + unsigned long val; + uint8_t flags; + int r; + + r = kstrtoul(buf, 10, &val); + if (r) + return r; + + if (val >= uma_info->num_entries) + return -EINVAL; + + val = array_index_nospec(val, uma_info->num_entries); + opt = &uma_info->entries[val]; + + if (!(opt->flags & AMDGPU_UMA_FLAG_AUTO) && + !(opt->flags & AMDGPU_UMA_FLAG_CUSTOM)) {+ drm_err_once(ddev, "Option %lu not supported due to lack of Custom/Auto flag", val);+ return -EINVAL; + } + + flags = opt->flags; + flags &= ~((flags & AMDGPU_UMA_FLAG_AUTO) >> 1); + + guard(mutex)(&uma_info->update_lock); + + r = amdgpu_acpi_set_uma_allocation_size(adev, val, flags); + if (r) + return r; + + uma_info->uma_option_index = val; + + return count; +} +static DEVICE_ATTR_RW(carveout); + +static struct attribute *amdgpu_uma_attrs[] = { + &dev_attr_carveout.attr, + &dev_attr_carveout_options.attr, + NULL +}; + +const struct attribute_group amdgpu_uma_attr_group = { + .name = "uma", + .attrs = amdgpu_uma_attrs +}; + +static void amdgpu_uma_sysfs_init(struct amdgpu_device *adev) +{ + int rc; + + if (!(adev->flags & AMD_IS_APU)) + return; + + if (!amdgpu_acpi_is_set_uma_allocation_size_supported()) + return; ++ rc = amdgpu_atomfirmware_get_uma_carveout_info(adev, &adev- >uma_info);+ if (rc) { + drm_dbg(adev_to_drm(adev), + "Failed to parse UMA carveout info from VBIOS: %d\n", rc); + goto out_info; + } + + mutex_init(&adev->uma_info.update_lock); + + rc = devm_device_add_group(adev->dev, &amdgpu_uma_attr_group); + if (rc) {+ drm_dbg(adev_to_drm(adev), "Failed to add UMA carveout sysfs interfaces %d\n", rc);+ goto out_attr; + } + + return; + +out_attr: + mutex_destroy(&adev->uma_info.update_lock); +out_info: + return; +} + +static void amdgpu_uma_sysfs_fini(struct amdgpu_device *adev) +{ + struct amdgpu_uma_carveout_info *uma_info = &adev->uma_info; + + if (!amdgpu_acpi_is_set_uma_allocation_size_supported()) + return; + + mutex_destroy(&uma_info->update_lock); + uma_info->num_entries = 0; +} + static void amdgpu_device_get_pcie_info(struct amdgpu_device *adev); /**@@ -4492,6 +4633,7 @@ static int amdgpu_device_sys_interface_init(struct amdgpu_device *adev)amdgpu_fru_sysfs_init(adev); amdgpu_reg_state_sysfs_init(adev); amdgpu_xcp_sysfs_init(adev); + amdgpu_uma_sysfs_init(adev); return r; }@@ -4507,6 +4649,7 @@ static void amdgpu_device_sys_interface_fini(struct amdgpu_device *adev)amdgpu_reg_state_sysfs_fini(adev); amdgpu_xcp_sysfs_fini(adev); + amdgpu_uma_sysfs_fini(adev); } /**
