kernel/linux.git/arch/x86, branch v5.10.258

Revert "x86/vdso: Fix output operand size of RDPID"

2026-06-01T15:29:49+00:00

This reverts commit f097ba74116fce394160c919bb2039b60fc64159. Signed-off-by: Sasha Levin

KVM: nSVM: Clear GIF on nested #VMEXIT(INVALID)

2026-06-01T15:29:20+00:00

commit f85a6ce06e4a0d49652f57967a649ab09e06287c upstream. According to the APM, GIF is set to 0 on any #VMEXIT, including an #VMEXIT(INVALID) due to failed consistency checks. Clear GIF on consistency check failures. Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260303003421.2185681-11-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nSVM: Ensure AVIC is inhibited when restoring a vCPU to guest mode

2026-06-01T15:29:20+00:00

commit 24f7d36b824b65cf1a2db3db478059187b2a37b0 upstream. On nested VMRUN, KVM ensures AVIC is inhibited by requesting KVM_REQ_APICV_UPDATE, triggering a check of inhibit reasons, finding APICV_INHIBIT_REASON_NESTED, and disabling AVIC. However, when KVM_SET_NESTED_STATE is performed on a vCPU not in guest mode with AVIC enabled, KVM_REQ_APICV_UPDATE is not requested, and AVIC is not inhibited. Request KVM_REQ_APICV_UPDATE in the KVM_SET_NESTED_STATE path if AVIC is active, similar to the nested VMRUN path. Fixes: f44509f849fe ("KVM: x86: SVM: allow AVIC to co-exist with a nested guest running") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260224225017.3303870-1-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2

2026-06-01T15:29:20+00:00

commit 03bee264f8ebfd39e0254c98e112d033a7aa9055 upstream. After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs fields written by the CPU from vmcb02 to the cached vmcb12. This is because the cached vmcb12 is used as the authoritative copy of some of the controls, and is the payload when saving/restoring nested state. int_state is also written by the CPU, specifically bit 0 (i.e. SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites what KVM_SET_NESTED_STATE restored in int_state). However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an interrupt shadow would be restored into vmcb01 instead of vmcb02. This would mostly be benign for L1 (delays an interrupt), but not for L2. For L2, the vCPU could hang (e.g. if a wakeup interrupt is delivered before a HLT that should have been in an interrupt shadow). Sync int_state to the cached vmcb12 in nested_sync_control_from_vmcb02() to avoid this problem. With that, KVM_SET_NESTED_STATE restores the correct interrupt shadow state, and if KVM_SET_VCPU_EVENTS follows it would overwrite it with the same value. Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE") CC: stable@vger.kernel.org Signed-off-by: Yosry Ahmed Link: https://patch.msgid.link/20260225005950.3739782-3-yosry@kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

x86/uprobes: Fix XOL allocation failure for 32-bit tasks

2026-06-01T15:29:15+00:00

[ Upstream commit d55c571e4333fac71826e8db3b9753fadfbead6a ] This script #!/usr/bin/bash echo 0 > /proc/sys/kernel/randomize_va_space echo 'void main(void) {}' > TEST.c # -fcf-protection to ensure that the 1st endbr32 insn can't be emulated gcc -m32 -fcf-protection=branch TEST.c -o test bpftrace -e 'uprobe:./test:main {}' -c ./test "hangs", the probed ./test task enters an endless loop. The problem is that with randomize_va_space == 0 get_unmapped_area(TASK_SIZE - PAGE_SIZE) called by xol_add_vma() can not just return the "addr == TASK_SIZE - PAGE_SIZE" hint, this addr is used by the stack vma. arch_get_unmapped_area_topdown() doesn't take TIF_ADDR32 into account and in_32bit_syscall() is false, this leads to info.high_limit > TASK_SIZE. vm_unmapped_area() happily returns the high address > TASK_SIZE and then get_unmapped_area() returns -ENOMEM after the "if (addr > TASK_SIZE - len)" check. handle_swbp() doesn't report this failure (probably it should) and silently restarts the probed insn. Endless loop. I think that the right fix should change the x86 get_unmapped_area() paths to rely on TIF_ADDR32 rather than in_32bit_syscall(). Note also that if CONFIG_X86_X32_ABI=y, in_x32_syscall() falsely returns true in this case because ->orig_ax = -1. But we need a simple fix for -stable, so this patch just sets TS_COMPAT if the probed task is 32-bit to make in_ia32_syscall() true. Fixes: 1b028f784e8c ("x86/mm: Introduce mmap_compat_base() for 32-bit mmap()") Reported-by: Paulo Andrade Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/all/aV5uldEvV7pb4RA8@redhat.com/ Cc: stable@vger.kernel.org Link: https://patch.msgid.link/aWO7Fdxn39piQnxu@redhat.com Signed-off-by: Greg Kroah-Hartman

KVM: x86: Use scratch field in MMIO fragment to hold small write values

2026-06-01T15:29:12+00:00

commit 0b16e69d17d8c35c5c9d5918bf596c75a44655d3 upstream. When exiting to userspace to service an emulated MMIO write, copy the to-be-written value to a scratch field in the MMIO fragment if the size of the data payload is 8 bytes or less, i.e. can fit in a single chunk, instead of pointing the fragment directly at the source value. This fixes a class of use-after-free bugs that occur when the emulator initiates a write using an on-stack, local variable as the source, the write splits a page boundary, *and* both pages are MMIO pages. Because KVM's ABI only allows for physically contiguous MMIO requests, accesses that split MMIO pages are separated into two fragments, and are sent to userspace one at a time. When KVM attempts to complete userspace MMIO in response to KVM_RUN after the first fragment, KVM will detect the second fragment and generate a second userspace exit, and reference the on-stack variable. The issue is most visible if the second KVM_RUN is performed by a separate task, in which case the stack of the initiating task can show up as truly freed data. ================================================================== BUG: KASAN: use-after-free in complete_emulated_mmio+0x305/0x420 Read of size 1 at addr ffff888009c378d1 by task syz-executor417/984 CPU: 1 PID: 984 Comm: syz-executor417 Not tainted 5.10.0-182.0.0.95.h2627.eulerosv2r13.x86_64 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0xbe/0xfd print_address_description.constprop.0+0x19/0x170 __kasan_report.cold+0x6c/0x84 kasan_report+0x3a/0x50 check_memory_region+0xfd/0x1f0 memcpy+0x20/0x60 complete_emulated_mmio+0x305/0x420 kvm_arch_vcpu_ioctl_run+0x63f/0x6d0 kvm_vcpu_ioctl+0x413/0xb20 __se_sys_ioctl+0x111/0x160 do_syscall_64+0x30/0x40 entry_SYSCALL_64_after_hwframe+0x67/0xd1 RIP: 0033:0x42477d Code: <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007faa8e6890e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004d7338 RCX: 000000000042477d RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00000000004d7330 R08: 00007fff28d546df R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004d733c R13: 0000000000000000 R14: 000000000040a200 R15: 00007fff28d54720 The buggy address belongs to the page: page:0000000029f6a428 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9c37 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffea0000270dc8 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888009c37780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888009c37800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888009c37880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888009c37900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888009c37980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== The bug can also be reproduced with a targeted KVM-Unit-Test by hacking KVM to fill a large on-stack variable in complete_emulated_mmio(), i.e. by overwrite the data value with garbage. Limit the use of the scratch fields to 8-byte or smaller accesses, and to just writes, as larger accesses and reads are not affected thanks to implementation details in the emulator, but add a sanity check to ensure those details don't change in the future. Specifically, KVM never uses on-stack variables for accesses larger that 8 bytes, e.g. uses an operand in the emulator context, and *all* reads are buffered through the mem_read cache. Note! Using the scratch field for reads is not only unnecessary, it's also extremely difficult to handle correctly. As above, KVM buffers all reads through the mem_read cache, and heavily relies on that behavior when re-emulating the instruction after a userspace MMIO read exit. If a read splits a page, the first page is NOT an MMIO page, and the second page IS an MMIO page, then the MMIO fragment needs to point at _just_ the second chunk of the destination, i.e. its position in the mem_read cache. Taking the "obvious" approach of copying the fragment value into the destination when re-emulating the instruction would clobber the first chunk of the destination, i.e. would clobber the data that was read from guest memory. Fixes: f78146b0f923 ("KVM: Fix page-crossing MMIO") Suggested-by: Yashu Zhang Reported-by: Yashu Zhang Closes: https://lore.kernel.org/all/369eaaa2b3c1425c85e8477066391bc7@huawei.com Cc: stable@vger.kernel.org Tested-by: Tom Lendacky Tested-by: Rick Edgecombe Link: https://patch.msgid.link/20260225012049.920665-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION

2026-06-01T15:29:12+00:00

commit 8acffeef5ef720c35e513e322ab08e32683f32f2 upstream. Drop the WARN in sev_pin_memory() on npages overflowing an int, as the WARN is comically trivially to trigger from userspace, e.g. by doing: struct kvm_enc_region range = { .addr = 0, .size = -1ul, }; __vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range); Note, the checks in sev_mem_enc_register_region() that presumably exist to verify the incoming address+size are completely worthless, as both "addr" and "size" are u64s and SEV is 64-bit only, i.e. they _can't_ be greater than ULONG_MAX. That wart will be cleaned up in the near future. if (range->addr > ULONG_MAX || range->size > ULONG_MAX) return -EINVAL; Opportunistically add a comment to explain why the code calculates the number of pages the "hard" way, e.g. instead of just shifting @ulen. Fixes: 78824fabc72e ("KVM: SVM: fix svn_pin_memory()'s use of get_user_pages_fast()") Cc: stable@vger.kernel.org Reviewed-by: Liam Merwick Tested-by: Liam Merwick Link: https://patch.msgid.link/20260313003302.3136111-2-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman

x86/CPU/AMD: Prevent improper isolation of shared resources in Zen2's op cache

2026-05-15T12:48:07+00:00

commit c21b90f77687075115d989e53a8ec5e2bb427ab1 upstream. Make sure resources are not improperly shared in the op cache and cause instruction corruption this way. Signed-off-by: Prathyushi Nangia Co-developed-by: Borislav Petkov (AMD) Signed-off-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

x86/CPU/AMD: Add X86_FEATURE_ZEN1

2026-05-15T12:48:07+00:00

Commit 232afb557835d6f6859c73bf610bad308c96b131 upstream. Add a synthetic feature flag specifically for first generation Zen machines. There's need to have a generic flag for all Zen generations so make X86_FEATURE_ZEN be that flag. Fixes: 30fa92832f40 ("x86/CPU/AMD: Add ZenX generations flags") Suggested-by: Brian Gerst Suggested-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/dc3835e3-0731-4230-bbb9-336bbe3d042b@amd.com Signed-off-by: Greg Kroah-Hartman

x86/CPU/AMD: Rename init_amd_zn() to init_amd_zen_common()

2026-05-15T12:48:07+00:00

Commit 7c81ad8e8bc28a1847e87c5afe1bae6bffb2f73e upstream. Call it from all Zen init functions. Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Nikolay Borisov Link: http://lore.kernel.org/r/20231120104152.13740-7-bp@alien8.de Signed-off-by: Greg Kroah-Hartman