kernel/linux.git/arch/x86/include, branch v6.6.155

x86/bugs: Make Safe-RET robust against interrupt injection

2026-08-07T06:10:47+00:00

commit 7e7f81cf6f5ca3311e526308f55d7c54d3ba71f9 upstream. An attacker injecting interrupts while the Safe-RET mitigation executes on machines affected by SRSO can neutralize the safe return sequence, potentially leading to data leakage through speculative execution. Fixup register state as if the Safe-RET sequence executed successfully by "emulating" it, in a manner of speaking, and avoid executing a RET instruction after returning from the interrupt. Co-developed-by: David Kaplan Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

Revert "x86/bugs: Make Safe-RET robust against interrupt injection"

2026-08-07T06:10:47+00:00

This reverts commit 608c8f5dccaaf8b8d2b28c0fbdd439d144be62b0 which is commit 7e7f81cf6f5ca3311e526308f55d7c54d3ba71f9 upstream. It was incorrect, a more correct fix will be applied next. Signed-off-by: Greg Kroah-Hartman

x86/bugs: Make Safe-RET robust against interrupt injection

2026-08-06T17:25:30+00:00

x86/bugs: Enable IBPB flush on BPF JIT allocation

2026-07-24T14:02:56+00:00

commit a3af84b0fa00ead01fcd0e28b5d773ff25990a0d upstream. Enable hardening against JIT spraying when Spectre-v2 mitigations are in use. Specifically, issue an IBPB flush on BPF JIT memory reuse. Skip enabling the IBPB flush if the BPF dispatcher is already using a retpoline sequence. This hardening applies only when BPF-JIT is in use. Guard the enabling under CONFIG_BPF_JIT so that bugs.c still builds with CONFIG_BPF_JIT=n. [ pawan: Use entry_ibpb() instead of write_ibpb(). JIT hardening enable moved to spectre_v2_select_mitigation() because there is no spectre_v2_apply_mitigation()] Signed-off-by: Pawan Gupta Acked-by: Daniel Borkmann Acked-by: Dave Hansen Signed-off-by: Daniel Borkmann Signed-off-by: Sasha Levin

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

2026-06-01T15:43:04+00:00

This reverts commit db82a94b0c109e7697a593f36783e7ef36073983. Signed-off-by: Sasha Levin

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

2026-05-15T12:50:29+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

KVM: x86: Use __DECLARE_FLEX_ARRAY() for UAPI structures with VLAs

2026-04-27T13:23:34+00:00

[ Upstream commit 2619da73bb2f10d88f7e1087125c40144fdf0987 ] Commit 94dfc73e7cf4 ("treewide: uapi: Replace zero-length arrays with flexible-array members") broke the userspace API for C++. These structures ending in VLAs are typically a *header*, which can be followed by an arbitrary number of entries. Userspace typically creates a larger structure with some non-zero number of entries, for example in QEMU's kvm_arch_get_supported_msr_feature(): struct { struct kvm_msrs info; struct kvm_msr_entry entries[1]; } msr_data = {}; While that works in C, it fails in C++ with an error like: flexible array member 'kvm_msrs::entries' not at end of 'struct msr_data' Fix this by using __DECLARE_FLEX_ARRAY() for the VLA, which uses [0] for C++ compilation. Fixes: 94dfc73e7cf4 ("treewide: uapi: Replace zero-length arrays with flexible-array members") Cc: stable@vger.kernel.org Signed-off-by: David Woodhouse Link: https://patch.msgid.link/3abaf6aefd6e5efeff3b860ac38421d9dec908db.camel@infradead.org [sean: tag for stable@] Signed-off-by: Sean Christopherson [ applied `__DECLARE_FLEX_ARRAY(char, name)` change directly instead of inside missing `#ifdef __KERNEL__` else branch ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

KVM: nVMX: Fold requested virtual interrupt check into has_nested_events()

2026-04-27T13:23:32+00:00

[ Upstream commit 321ef62b0c5f6f57bb8500a2ca5986052675abbf ] Check for a Requested Virtual Interrupt, i.e. a virtual interrupt that is pending delivery, in vmx_has_nested_events() and drop the one-off kvm_x86_ops.guest_apic_has_interrupt() hook. In addition to dropping a superfluous hook, this fixes a bug where KVM would incorrectly treat virtual interrupts _for L2_ as always enabled due to kvm_arch_interrupt_allowed(), by way of vmx_interrupt_blocked(), treating IRQs as enabled if L2 is active and vmcs12 is configured to exit on IRQs, i.e. KVM would treat a virtual interrupt for L2 as a valid wake event based on L1's IRQ blocking status. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240607172609.3205077-6-seanjc@google.com Signed-off-by: Sean Christopherson Cc: Taeyang Lee <0wn@theori.io> [sean: deal with lack of vmx/main.c and vmx/x86_ops.h] Signed-off-by: Sean Christopherson Signed-off-by: Sasha Levin

x86/CPU: Fix FPDSS on Zen1

2026-04-18T08:39:49+00:00

commit e55d98e7756135f32150b9b8f75d580d0d4b2dd3 upstream. Zen1's hardware divider can leave, under certain circumstances, partial results from previous operations. Those results can be leaked by another, attacker thread. Fix that with a chicken bit. Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

x86/sev: Allow IBPB-on-Entry feature for SNP guests

2026-03-25T10:05:56+00:00

[ Upstream commit 9073428bb204d921ae15326bb7d4558d9d269aab ] The SEV-SNP IBPB-on-Entry feature does not require a guest-side implementation. It was added in Zen5 h/w, after the first SNP Zen implementation, and thus was not accounted for when the initial set of SNP features were added to the kernel. In its abundant precaution, commit 8c29f0165405 ("x86/sev: Add SEV-SNP guest feature negotiation support") included SEV_STATUS' IBPB-on-Entry bit as a reserved bit, thereby masking guests from using the feature. Allow guests to make use of IBPB-on-Entry when supported by the hypervisor, as the bit is now architecturally defined and safe to expose. Fixes: 8c29f0165405 ("x86/sev: Add SEV-SNP guest feature negotiation support") Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Nikunj A Dadhania Reviewed-by: Tom Lendacky Cc: stable@kernel.org Link: https://patch.msgid.link/20260203222405.4065706-2-kim.phillips@amd.com [ No SECURE_AVIC ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman