[PATCH v2] drm/xe/vram: fix ccs offset calculation

Fri Sep 13 22:36:23 UTC 2024

On Fri, Sep 13, 2024 at 01:00:24PM GMT, Matthew Auld wrote:
>Spec says SW is expected to round up to the nearest 128K, if not already
>aligned for the CC unit view of CCS. We are seeing the assert sometimes
>pop on BMG to tell us that there is a hole between GSM and CCS, as well

may you paste the waning here? Just got a random BMG from the pile and
have some may-be-related warnings showing up. And this patch didn't
help:

[ 1109.275389] ------------[ cut here ]------------
[ 1109.275392] xe 0000:03:00.0: [drm] Assertion `offset == (xe_mmio_read64_2x32(&_Generic(gt, const struct xe_gt * : (const struct xe_tile *)((gt)->tile), struct xe_gt * : (gt)->tile)->mmio, ((const struct xe_reg){ .addr = 0x108100, })) - ccs_size)` failed!
                platform: BATTLEMAGE subplatform: 1
                graphics: Xe2_LPG / Xe2_HPG 20.01 step A0
                media: Xe2_LPM / Xe2_HPM 13.01 step A1
                Hole between CCS and GSM.
[ 1109.275415] WARNING: CPU: 6 PID: 3377 at drivers/gpu/drm/xe/xe_vram.c:188 tile_vram_size+0x26d/0x500 [xe]
[ 1109.275540] Modules linked in: xe(+) snd_hda_intel mei_gsc_proxy mei_gsc drm_gpuvm i2c_algo_bit drm_ttm_helper ttm gpu_sched drm_suballoc_helper drm_exec drm_display_helper drm_kunit_helpers drm_kms_helper kunit drm_buddy xt_conntrack nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xfrm_user xfrm_algo xt_addrtype nft_compat nf_tables br_netfilter bridge stp llc overla
y sunrpc binfmt_misc intel_rapl_msr intel_rapl_common intel_uncore_frequency intel_uncore_frequency_common snd_sof_pci_intel_tgl x86_pkg_temp_thermal snd_sof_pci_intel_cnl intel_powerclamp snd_sof_intel_hda_generic snd_sof_pci snd_sof_xtensa_dsp snd_sof_intel_hda_common coretemp snd_soc_hdac_hda cmdlinepart snd_sof_intel_hda snd_sof spi_nor kvm_intel snd_sof_utils mtd snd_soc_acpi_intel_match snd_soc_acpi kvm snd_intel_d
spcfg snd_hda_codec snd_hwdep snd_sof_intel_hda_mlink rapl wmi_bmof snd_hda_ext_core intel_cstate snd_hda_core snd_soc_core snd_compress snd_pcm snd_timer nls_iso8859_1 snd i2c_i801
[ 1109.275604]  spi_intel_pci idma64 soundcore i2c_smbus spi_intel mei_pxp mei_hdcp intel_pmc_core input_leds video intel_vsec joydev pmt_telemetry wmi pmt_class acpi_tad acpi_pad mac_hid mei_me mei sch_fq_codel msr drm efi_pstore dm_multipath nfnetlink ip_tables x_tables autofs4 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 hid_generic usbhid hid crct10dif_pclmul crc32_pclmul poly
val_clmulni polyval_generic ghash_clmulni_intel sha512_ssse3 sha256_ssse3 sha1_ssse3 r8169 realtek pinctrl_alderlake aesni_intel crypto_simd cryptd [last unloaded: xe]
[ 1109.275651] CPU: 6 UID: 0 PID: 3377 Comm: xe_module_load Kdump: loaded Tainted: G        W          6.11.0-rc7-xe+ #1
[ 1109.275654] Tainted: [W]=WARN
[ 1109.275656] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023
[ 1109.275657] RIP: 0010:tile_vram_size+0x26d/0x500 [xe]
[ 1109.275753] Code: 55 b0 41 52 8b 4d a8 51 8b 45 b8 48 c7 c1 a0 dc 1d a1 50 4c 8b 5d a0 41 53 44 8b 4d 9c 4c 8b 45 90 48 8b 55 88 e8 83 19 17 e0 <0f> 0b 48 83 c4 40 eb 11 49 8d 7d 20 be 00 81 10 00 e8 ed d0 fc ff
[ 1109.275755] RSP: 0018:ffffc90001a0b418 EFLAGS: 00010282
[ 1109.275757] RAX: 0000000000000000 RBX: ffffc90001a0b538 RCX: 0000000000000027
[ 1109.275759] RDX: ffff88885f321a08 RSI: 0000000000000001 RDI: ffff88885f321a00
[ 1109.275760] RBP: ffffc90001a0b4e0 R08: 0000000000000000 R09: 0000000000000003
[ 1109.275761] R10: ffffc90001a0b270 R11: ffff88885ebfffe8 R12: 0000000000000001
[ 1109.275763] R13: 000000027bc40000 R14: ffffffffa1219868 R15: ffff888161660078
[ 1109.275764] FS:  00007f02bcb28c40(0000) GS:ffff88885f300000(0000) knlGS:0000000000000000
[ 1109.275766] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1109.275767] CR2: 00005606882c0f00 CR3: 00000001307ee000 CR4: 0000000000750ef0
[ 1109.275769] PKRU: 55555554
[ 1109.275770] Call Trace:
[ 1109.275771]  <TASK>
[ 1109.275773]  ? show_regs+0x64/0x70
[ 1109.275778]  ? __warn+0x8e/0x1a0
[ 1109.275783]  ? tile_vram_size+0x26d/0x500 [xe]
[ 1109.275867]  ? report_bug+0x171/0x1a0
[ 1109.275872]  ? handle_bug+0x44/0x90
[ 1109.275876]  ? exc_invalid_op+0x18/0x70
[ 1109.275879]  ? asm_exc_invalid_op+0x1b/0x20
[ 1109.275886]  ? tile_vram_size+0x26d/0x500 [xe]
[ 1109.275965]  ? tile_vram_size+0x26d/0x500 [xe]
[ 1109.276046]  xe_vram_probe+0xa1/0x860 [xe]

Is this the one you're talking about? I don't really remember seeing
this warning before. So maybe we let a regression in?

Lucas De Marchi

>as popping other asserts with having a vram size with strange alignment,
>which is likely caused by misaligned offset here.
>
>BSpec: 68023
>Fixes: b5c2ca0372dc ("drm/xe/xe2hpg: Determine flat ccs offset for vram")
>Signed-off-by: Matthew Auld <matthew.auld at intel.com>
>Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
>Cc: Akshata Jahagirdar <akshata.jahagirdar at intel.com>
>Cc: Shuicheng Lin <shuicheng.lin at intel.com>
>Cc: Matt Roper <matthew.d.roper at intel.com>
>Cc: <stable at vger.kernel.org> # v6.10+
>---
> drivers/gpu/drm/xe/xe_vram.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/drivers/gpu/drm/xe/xe_vram.c b/drivers/gpu/drm/xe/xe_vram.c
>index 7e765b1499b1..8e65cb4cc477 100644
>--- a/drivers/gpu/drm/xe/xe_vram.c
>+++ b/drivers/gpu/drm/xe/xe_vram.c
>@@ -181,6 +181,7 @@ static inline u64 get_flat_ccs_offset(struct xe_gt *gt, u64 tile_size)
>
> 		offset = offset_hi << 32; /* HW view bits 39:32 */
> 		offset |= offset_lo << 6; /* HW view bits 31:6 */
>+		offset = round_up(offset, SZ_128K); /* SW must round up to nearest 128K */
> 		offset *= num_enabled; /* convert to SW view */
>
> 		/* We don't expect any holes */
>-- 
>2.46.0
>