49147beb0c
When running as a paravirtualized guest under Xen, Linux is using
"lazy mode" for issuing hypercalls which don't need to take immediate
effect in order to improve performance (examples are e.g. multiple
PTE changes).
There are two different lazy modes defined: MMU and CPU lazy mode.
Today it is not possible to nest multiple lazy mode sections, even if
they are of the same kind. A recent change in memory management added
nesting of MMU lazy mode sections, resulting in a regression when
running as Xen PV guest.
Technically there is no reason why nesting of multiple sections of the
same kind of lazy mode shouldn't be allowed. So add support for that
for fixing the regression.
Fixes: bcc6cc8325 ("mm: add default definition of set_ptes()")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20230913113828.18421-4-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
103 lines
3.1 KiB
C
103 lines
3.1 KiB
C
/******************************************************************************
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* hypervisor.h
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*
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* Linux-specific hypervisor handling.
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*
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* Copyright (c) 2002-2004, K A Fraser
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef _ASM_X86_XEN_HYPERVISOR_H
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#define _ASM_X86_XEN_HYPERVISOR_H
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extern struct shared_info *HYPERVISOR_shared_info;
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extern struct start_info *xen_start_info;
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#include <asm/bug.h>
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#include <asm/processor.h>
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#define XEN_SIGNATURE "XenVMMXenVMM"
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static inline uint32_t xen_cpuid_base(void)
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{
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return hypervisor_cpuid_base(XEN_SIGNATURE, 2);
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}
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struct pci_dev;
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#ifdef CONFIG_XEN_PV_DOM0
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bool xen_initdom_restore_msi(struct pci_dev *dev);
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#else
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static inline bool xen_initdom_restore_msi(struct pci_dev *dev) { return true; }
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#endif
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#ifdef CONFIG_HOTPLUG_CPU
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void xen_arch_register_cpu(int num);
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void xen_arch_unregister_cpu(int num);
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#endif
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#ifdef CONFIG_PVH
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void __init xen_pvh_init(struct boot_params *boot_params);
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void __init mem_map_via_hcall(struct boot_params *boot_params_p);
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#endif
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/* Lazy mode for batching updates / context switch */
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enum xen_lazy_mode {
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XEN_LAZY_NONE,
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XEN_LAZY_MMU,
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XEN_LAZY_CPU,
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};
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DECLARE_PER_CPU(enum xen_lazy_mode, xen_lazy_mode);
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DECLARE_PER_CPU(unsigned int, xen_lazy_nesting);
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static inline void enter_lazy(enum xen_lazy_mode mode)
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{
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enum xen_lazy_mode old_mode = this_cpu_read(xen_lazy_mode);
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if (mode == old_mode) {
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this_cpu_inc(xen_lazy_nesting);
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return;
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}
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BUG_ON(old_mode != XEN_LAZY_NONE);
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this_cpu_write(xen_lazy_mode, mode);
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}
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static inline void leave_lazy(enum xen_lazy_mode mode)
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{
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BUG_ON(this_cpu_read(xen_lazy_mode) != mode);
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if (this_cpu_read(xen_lazy_nesting) == 0)
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this_cpu_write(xen_lazy_mode, XEN_LAZY_NONE);
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else
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this_cpu_dec(xen_lazy_nesting);
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}
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enum xen_lazy_mode xen_get_lazy_mode(void);
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#endif /* _ASM_X86_XEN_HYPERVISOR_H */
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