lwn.git/arch/x86/xen, branch master

x86/xen: Tolerate nested XEN_LAZY_MMU entering/leaving

2026-05-14T16:33:05+00:00

With the support of nested lazy mmu sections it can happen that arch_enter_lazy_mmu_mode() is being called twice without a call of arch_leave_lazy_mmu_mode() in between, as the lazy_mmu_*() helpers are not disabling preemption when checking for nested lazy mmu sections. This is a problem when running as a Xen PV guest, as xen_enter_lazy_mmu() and xen_leave_lazy_mmu() don't tolerate this case. Fix that in xen_enter_lazy_mmu() and xen_leave_lazy_mmu() in order not to hurt all other lazy mmu mode users. Fixes: 291b3abed657 ("x86/xen: use lazy_mmu_state when context-switching") Tested-by: Marek Marczykowski-Górecki Signed-off-by: Juergen Gross Message-ID: <20260508143933.493013-1-jgross@suse.com>

x86/xen: Fix xen_e820_swap_entry_with_ram()

2026-05-14T16:33:05+00:00

When swapping a not page-aligned E820 map entry with RAM, the start address of the modified entry is calculated wrong (the offset into the page is subtracted instead of being added to the page address). Fixes: be35d91c8880 ("xen: tolerate ACPI NVS memory overlapping with Xen allocated memory") Reported-by: Jan Beulich Reviewed-by: Jan Beulich Signed-off-by: Juergen Gross Message-ID: <20260505102417.208138-1-jgross@suse.com>

x86/xen: Fix a potential problem in xen_e820_resolve_conflicts()

2026-05-05T08:17:00+00:00

When fixing a conflict in xen_e820_resolve_conflicts(), the loop over the E820 map entries needs to be restarted, as the E820 map will have been modified by the fix. Otherwise entries might be skipped by accident. Fixes: be35d91c8880 ("xen: tolerate ACPI NVS memory overlapping with Xen allocated memory") Signed-off-by: Juergen Gross Signed-off-by: Ingo Molnar Cc: xen-devel@lists.xenproject.org Link: https://patch.msgid.link/20260505080653.197775-1-jgross@suse.com

Merge tag 'x86-cleanups-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-14T21:03:27+00:00

Pull x86 cleanups from Ingo Molnar: - Consolidate AMD and Hygon cases in parse_topology() (Wei Wang) - asm constraints cleanups in __iowrite32_copy() (Uros Bizjak) - Drop AMD Extended Interrupt LVT macros (Naveen N Rao) - Don't use REALLY_SLOW_IO for delays (Juergen Gross) - paravirt cleanups (Juergen Gross) - FPU code cleanups (Borislav Petkov) - split-lock handling code cleanups (Borislav Petkov, Ronan Pigott) * tag 'x86-cleanups-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu: Correct the comment explaining what xfeatures_in_use() does x86/split_lock: Don't warn about unknown split_lock_detect parameter x86/fpu: Correct misspelled xfeaures_to_write local var x86/apic: Drop AMD Extended Interrupt LVT macros x86/cpu/topology: Consolidate AMD and Hygon cases in parse_topology() block/floppy: Don't use REALLY_SLOW_IO for delays x86/paravirt: Replace io_delay() hook with a bool x86/irqflags: Preemptively move include paravirt.h directive where it belongs x86/split_lock: Restructure the unwieldy switch-case in sld_state_show() x86/local: Remove trailing semicolon from _ASM_XADD in local_add_return() x86/asm: Use inout "+" asm onstraint modifiers in __iowrite32_copy()

x86/acpi: Add acpi_get_cpu_uid() for unified ACPI CPU UID retrieval

2026-04-06T14:55:15+00:00

As a step towards unifying the interface for retrieving ACPI CPU UID across architectures, introduce a new function acpi_get_cpu_uid() for x86. While at it, add input validation to make the code more robust. Update Xen-related code to use acpi_get_cpu_uid() instead of the legacy cpu_acpi_id() function, and remove the now-unused cpu_acpi_id() to clean up redundant code. Signed-off-by: Chengwen Feng Reviewed-by: Jonathan Cameron Reviewed-by: Juergen Gross Link: https://patch.msgid.link/20260401081640.26875-5-fengchengwen@huawei.com Signed-off-by: Rafael J. Wysocki

x86/paravirt: Replace io_delay() hook with a bool

2026-03-22T07:43:05+00:00

The io_delay() paravirt hook is in no way performance critical and all users setting it to a different function than native_io_delay() are using an empty function as replacement. Allow replacing the hook with a bool indicating whether native_io_delay() should be called. [ bp: Massage commit message. ] Signed-off-by: Juergen Gross Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Ingo Molnar Link: https://patch.msgid.link/20260119182632.596369-3-jgross@suse.com

Merge tag 'for-linus-7.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2026-03-07T15:44:32+00:00

Pull xen fixes from Juergen Gross: - a cleanup of arch/x86/kernel/head_64.S removing the pre-built page tables for Xen guests - a small comment update - another cleanup for Xen PVH guests mode - fix an issue with Xen PV-devices backed by driver domains * tag 'for-linus-7.0-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/xenbus: better handle backend crash xenbus: add xenbus_device parameter to xenbus_read_driver_state() x86/PVH: Use boot params to pass RSDP address in start_info page x86/xen: update outdated comment xen/acpi-processor: fix _CST detection using undersized evaluation buffer x86/xen: Build identity mapping page tables dynamically for XENPV

x86/xen: update outdated comment

2026-03-03T13:54:59+00:00

The function xen_flush_tlb_others() was renamed xen_flush_tlb_multi() by commit 4ce94eabac16 ("x86/mm/tlb: Flush remote and local TLBs concurrently"). Update the comment accordingly. Signed-off-by: kexinsun Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Message-ID: <20260224022424.1718-1-kexinsun@smail.nju.edu.cn>

x86/xen: Build identity mapping page tables dynamically for XENPV

2026-03-03T13:21:44+00:00

After commit 47ffe0578aee ("x86/pvh: Add 64bit relocation page tables"), the PVH entry uses a new set of page tables instead of the preconstructed page tables in head64.S. Since those preconstructed page tables are only used in XENPV now and XENPV does not actually need the preconstructed identity page tables directly, they can be filled in xen_setup_kernel_pagetable(). Therefore, build the identity mapping page table dynamically to remove the preconstructed page tables and make the code cleaner. Signed-off-by: Hou Wenlong Reviewed-by: Juergen Gross Acked-by: "Borislav Petkov (AMD)" Signed-off-by: Juergen Gross Message-ID: <453981eae7e8158307f971d1632d5023adbe03c3.1769074722.git.houwenlong.hwl@antgroup.com>

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\