From d9886a1a06cd355fc292987d22fb088a716691e0 Mon Sep 17 00:00:00 2001
From: Alistair Popple <apopple@nvidia.com>
Date: Wed, 9 Sep 2026 16:45:01 +1000
Subject: [PATCH] drm: nova: Add usable VRAM size to GPU info

Add a field to the GPU info structure containing the total usable
framebuffer size. The usable framebuffer excludes GSP carveouts and
other protected regions, so it may differ from the BAR size and total
physical VRAM.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
Link: https://patch.msgid.link/20260909064506.910162-9-apopple@nvidia.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 drivers/gpu/drm/nova/file.rs          |  2 ++
 drivers/gpu/nova-core/api.rs          |  6 ++++++
 drivers/gpu/nova-core/gpu.rs          |  6 ++----
 drivers/gpu/nova-core/gsp/commands.rs | 10 +++++++++-
 include/uapi/drm/nova_drm.h           |  6 ++++++
 5 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/nova/file.rs b/drivers/gpu/drm/nova/file.rs
index 1c026f6c2f87..988f639af116 100644
--- a/drivers/gpu/drm/nova/file.rs
+++ b/drivers/gpu/drm/nova/file.rs
@@ -42,10 +42,12 @@ impl GpuInfo {
     /// another documented default instead.
     fn new(reg_data: &DrmRegData<'_>) -> Result<Self> {
         let spec = reg_data.api.with(|api| api.get_ref().spec());
+        let gsp_static_info = reg_data.api.with(|api| api.get_ref().gsp_static_info());
 
         let info = uapi::drm_nova_info_gpu {
             architecture: spec.chipset.arch().into(),
             chipid: spec.chipset.into(),
+            vram_size: gsp_static_info.vram_size(),
         };
         Ok(Self(info))
     }
diff --git a/drivers/gpu/nova-core/api.rs b/drivers/gpu/nova-core/api.rs
index 876451dcc051..64f9ea442278 100644
--- a/drivers/gpu/nova-core/api.rs
+++ b/drivers/gpu/nova-core/api.rs
@@ -15,6 +15,7 @@
 pub use crate::gpu::Spec;
 
 use crate::gpu::Gpu;
+use crate::gsp::commands::GetGspStaticInfoReply;
 
 /// API handle for the auxiliary bus child drivers to interact with nova-core.
 pub struct NovaCoreApi<'bound> {
@@ -28,6 +29,11 @@ pub fn of(adev: &auxiliary::Device<Bound>) -> Result<NovaCoreApiHandle<'_>> {
         NovaCoreApiHandle::of(adev)
     }
 
+    /// Returns the GPU [`GetGspStaticInfoReply`].
+    pub fn gsp_static_info(&self) -> &GetGspStaticInfoReply {
+        &self.gpu.gsp_static_info
+    }
+
     /// Returns the GPU [`Spec`].
     pub fn spec(&self) -> &Spec {
         &self.gpu.spec
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index 190a14ea8189..fb6f8a86a503 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -336,7 +336,7 @@ struct GspResources<'gpu> {
 pub(crate) struct Gpu<'gpu> {
     pub(crate) spec: Spec,
     /// Static GPU information as provided by the GSP.
-    gsp_static_info: GetGspStaticInfoReply,
+    pub(crate) gsp_static_info: GetGspStaticInfoReply,
     /// GPU memory manager owning memory management resources.
     ///
     /// Must be kept declared *before* `gsp_resources`, so that its components are dropped while
@@ -473,9 +473,7 @@ pub(crate) fn new<'a>(
                     dev_dbg!(
                         dev,
                         "Total usable VRAM: {} MiB\n",
-                        info.usable_fb_regions.iter().fold(0u64, |res, region| res
-                            .saturating_add(region.end - region.start))
-                            / u64::SZ_1M
+                        info.vram_size() / u64::SZ_1M
                     );
                 }
 
diff --git a/drivers/gpu/nova-core/gsp/commands.rs b/drivers/gpu/nova-core/gsp/commands.rs
index e087c9e8c35c..c193149bc20e 100644
--- a/drivers/gpu/nova-core/gsp/commands.rs
+++ b/drivers/gpu/nova-core/gsp/commands.rs
@@ -212,7 +212,7 @@ fn init(&self) -> impl Init<Self::Command, Self::InitError> {
 }
 
 /// The reply from the GSP to the [`GetGspStaticInfo`] command.
-pub(crate) struct GetGspStaticInfoReply {
+pub struct GetGspStaticInfoReply {
     gpu_name: [u8; 64],
     /// BAR1 Page Directory Entry base address.
     pub(crate) bar1_pde_base: u64,
@@ -268,6 +268,14 @@ pub(crate) fn gpu_name(&self) -> core::result::Result<&str, GpuNameError> {
             .to_str()
             .map_err(GpuNameError::InvalidUtf8)
     }
+
+    /// Returns the total usable VRAM size in bytes, i.e. the summed lengths of all usable FB
+    /// regions.
+    pub fn vram_size(&self) -> u64 {
+        self.usable_fb_regions.iter().fold(0, |size, region| {
+            size.saturating_add(region.end - region.start)
+        })
+    }
 }
 
 pub(crate) use fw::commands::PowerStateLevel;
diff --git a/include/uapi/drm/nova_drm.h b/include/uapi/drm/nova_drm.h
index 079da428164d..97be2b54ce9b 100644
--- a/include/uapi/drm/nova_drm.h
+++ b/include/uapi/drm/nova_drm.h
@@ -182,6 +182,12 @@ struct drm_nova_info_gpu {
 	 * See &enum drm_nova_chipid for currently known chips.
 	 */
 	__u32 chipid;
+
+	/**
+	 * @vram_size: Amount of usable FB, excluding GSP carveouts and protected
+	 * regions.
+	 */
+	__u64 vram_size;
 };
 
 #define DRM_NOVA_GETPARAM		0x00