[6.6-velinux] Intel: SierreForest MAXPHYADDR support#41
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x56Jason wants to merge 2 commits into6.6-velinuxfrom
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[6.6-velinux] Intel: SierreForest MAXPHYADDR support#41x56Jason wants to merge 2 commits into6.6-velinuxfrom
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commit b628cb5 upstream. Use the GuestPhysBits field in CPUID.0x80000008 to communicate the max mappable GPA to userspace, i.e. the max GPA that is addressable by the CPU itself. Typically this is identical to the max effective GPA, except in the case where the CPU supports MAXPHYADDR > 48 but does not support 5-level TDP (the CPU consults bits 51:48 of the GPA only when walking the fifth level TDP page table entry). Enumerating the max mappable GPA via CPUID will allow guest firmware to map resources like PCI bars in the highest possible address space, while ensuring that the GPA is addressable by the CPU. Without precise knowledge about the max mappable GPA, the guest must assume that 5-level paging is unsupported and thus restrict its mappings to the lower 48 bits. Advertise the max mappable GPA via KVM_GET_SUPPORTED_CPUID as userspace doesn't have easy access to whether or not 5-level paging is supported, and to play nice with userspace VMMs that reflect the supported CPUID directly into the guest. AMD's APM (3.35) defines GuestPhysBits (EAX[23:16]) as: Maximum guest physical address size in bits. This number applies only to guests using nested paging. When this field is zero, refer to the PhysAddrSize field for the maximum guest physical address size. Tom Lendacky confirmed that the purpose of GuestPhysBits is software use and KVM can use it as described above. Real hardware always returns zero. Leave GuestPhysBits as '0' when TDP is disabled in order to comply with the APM's statement that GuestPhysBits "applies only to guest using nested paging". As above, guest firmware will likely create suboptimal mappings, but that is a very minor issue and not a functional concern. Intel-SIG: commit b628cb5 KVM: x86: Advertise max mappable GPA in CPUID.0x80000008.GuestPhysBits Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20240313125844.912415-3-kraxel@redhat.com [sean: massage changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Jason Zeng <jason.zeng@intel.com>
commit 980b8bc upstream. Use the max mappable GPA via GuestPhysBits advertised by KVM to calculate max_gfn. Currently some selftests (e.g. access_tracking_perf_test, dirty_log_test...) add RAM regions close to max_gfn, so guest may access GPA beyond its mappable range and cause infinite loop. Adjust max_gfn in vm_compute_max_gfn() since x86 selftests already overrides vm_compute_max_gfn() specifically to deal with goofy edge cases. Intel-SIG: commit 980b8bc KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits Reported-by: Yi Lai <yi1.lai@intel.com> Signed-off-by: Tao Su <tao1.su@linux.intel.com> Tested-by: Yi Lai <yi1.lai@intel.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20240513014003.104593-1-tao1.su@linux.intel.com [sean: tweak name, add comment and sanity check] Signed-off-by: Sean Christopherson <seanjc@google.com> Conflicts: tools/testing/selftests/kvm/include/x86_64/processor.h [jz: resolve simple context conflict] Signed-off-by: Jason Zeng <jason.zeng@intel.com>
guojinhui-liam
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Jun 17, 2025
commit 19468ed upstream. The cgroup1_hierarchy test uses setup_classid_environment to setup cgroupv1 environment. The problem is that the environment is set in /sys/fs/cgroup and therefore, if not run under an own mount namespace, effectively deletes all system cgroups: $ ls /sys/fs/cgroup | wc -l 27 $ sudo ./test_progs -t cgroup1_hierarchy #41/1 cgroup1_hierarchy/test_cgroup1_hierarchy:OK #41/2 cgroup1_hierarchy/test_root_cgid:OK #41/3 cgroup1_hierarchy/test_invalid_level:OK #41/4 cgroup1_hierarchy/test_invalid_cgid:OK #41/5 cgroup1_hierarchy/test_invalid_hid:OK #41/6 cgroup1_hierarchy/test_invalid_cgrp_name:OK #41/7 cgroup1_hierarchy/test_invalid_cgrp_name2:OK #41/8 cgroup1_hierarchy/test_sleepable_prog:OK #41 cgroup1_hierarchy:OK Summary: 1/8 PASSED, 0 SKIPPED, 0 FAILED $ ls /sys/fs/cgroup | wc -l 1 To avoid this, run setup_cgroup_environment first which will create an own mount namespace. This only affects the cgroupv1_hierarchy test as all other cgroup1 test progs already run setup_cgroup_environment prior to running setup_classid_environment. Also add a comment to the header of setup_classid_environment to warn against this invalid usage in future. Fixes: 3607692 ("selftests/bpf: Add selftests for cgroup1 hierarchy") Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240429112311.402497-1-vmalik@redhat.com Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
x56Jason
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Nov 10, 2025
…addr-6.6' into intel-6.6-velinux == Description == This is to backport the following 2 upstream commits to support SRF MAXPHYADDR. SRF doesn't support 5-level EPT but has 52-bit physical address(MAXPHYADDR). With some specific Qemu version, this can cause KVM infinite loop when guest BIOS puts RAM memory or 64-bit PCI BAR in high physical address. b628cb5 KVM: x86: Advertise max mappable GPA in CPUID.0x80000008.GuestPhysBits 980b8bc KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits == Test == - Sanity Test, build and run VM - On SRF platform, passthrough a NIC which has a 64-bit BAR to VM, the VM can boot successfully without hang.
jackYoung0915
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Mar 18, 2026
[ Upstream commit ecbf607 ] Fixes a hang thats triggered when MPV is run on a DCN401 dGPU: mpv --hwdec=vaapi --vo=gpu --hwdec-codecs=all and then enabling fullscreen playback (double click on the video) The following calltrace will be seen: [ 181.843989] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 181.843997] #PF: supervisor instruction fetch in kernel mode [ 181.844003] #PF: error_code(0x0010) - not-present page [ 181.844009] PGD 0 P4D 0 [ 181.844020] Oops: 0010 [#1] PREEMPT SMP NOPTI [ 181.844028] CPU: 6 PID: 1892 Comm: gnome-shell Tainted: G W OE 6.5.0-41-generic openvelinux#41~22.04.2-Ubuntu [ 181.844038] Hardware name: System manufacturer System Product Name/CROSSHAIR VI HERO, BIOS 6302 10/23/2018 [ 181.844044] RIP: 0010:0x0 [ 181.844079] Code: Unable to access opcode bytes at 0xffffffffffffffd6. [ 181.844084] RSP: 0018:ffffb593c2b8f7b0 EFLAGS: 00010246 [ 181.844093] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000004 [ 181.844099] RDX: ffffb593c2b8f804 RSI: ffffb593c2b8f7e0 RDI: ffff9e3c8e758400 [ 181.844105] RBP: ffffb593c2b8f7b8 R08: ffffb593c2b8f9c8 R09: ffffb593c2b8f96c [ 181.844110] R10: 0000000000000000 R11: 0000000000000000 R12: ffffb593c2b8f9c8 [ 181.844115] R13: 0000000000000001 R14: ffff9e3c88000000 R15: 0000000000000005 [ 181.844121] FS: 00007c6e323bb5c0(0000) GS:ffff9e3f85f80000(0000) knlGS:0000000000000000 [ 181.844128] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 181.844134] CR2: ffffffffffffffd6 CR3: 0000000140fbe000 CR4: 00000000003506e0 [ 181.844141] Call Trace: [ 181.844146] <TASK> [ 181.844153] ? show_regs+0x6d/0x80 [ 181.844167] ? __die+0x24/0x80 [ 181.844179] ? page_fault_oops+0x99/0x1b0 [ 181.844192] ? do_user_addr_fault+0x31d/0x6b0 [ 181.844204] ? exc_page_fault+0x83/0x1b0 [ 181.844216] ? asm_exc_page_fault+0x27/0x30 [ 181.844237] dcn20_get_dcc_compression_cap+0x23/0x30 [amdgpu] [ 181.845115] amdgpu_dm_plane_validate_dcc.constprop.0+0xe5/0x180 [amdgpu] [ 181.845985] amdgpu_dm_plane_fill_plane_buffer_attributes+0x300/0x580 [amdgpu] [ 181.846848] fill_dc_plane_info_and_addr+0x258/0x350 [amdgpu] [ 181.847734] fill_dc_plane_attributes+0x162/0x350 [amdgpu] [ 181.848748] dm_update_plane_state.constprop.0+0x4e3/0x6b0 [amdgpu] [ 181.849791] ? dm_update_plane_state.constprop.0+0x4e3/0x6b0 [amdgpu] [ 181.850840] amdgpu_dm_atomic_check+0xdfe/0x1760 [amdgpu] Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com> Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: David Nyström <david.nystrom@est.tech> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Description
This is to backport the following 2 upstream commits to support SRF MAXPHYADDR. SRF doesn't support 5-level EPT but has 52-bit physical address(MAXPHYADDR). With some specific Qemu version, this can cause KVM infinite loop when guest BIOS puts RAM memory or 64-bit PCI BAR in high physical address.
b628cb5 KVM: x86: Advertise max mappable GPA in CPUID.0x80000008.GuestPhysBits
980b8bc KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits
Test