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d1a928eac7
The main reason of this change is that unpopulated-alloc code cannot be used in its current form on Arm, but there is a desire to reuse it to avoid wasting real RAM pages for the grant/foreign mappings. The problem is that system "iomem_resource" is used for the address space allocation, but the really unallocated space can't be figured out precisely by the domain on Arm without hypervisor involvement. For example, not all device I/O regions are known by the time domain starts creating grant/foreign mappings. And following the advise from "iomem_resource" we might end up reusing these regions by a mistake. So, the hypervisor which maintains the P2M for the domain is in the best position to provide unused regions of guest physical address space which could be safely used to create grant/foreign mappings. Introduce new helper arch_xen_unpopulated_init() which purpose is to create specific Xen resource based on the memory regions provided by the hypervisor to be used as unused space for Xen scratch pages. If arch doesn't define arch_xen_unpopulated_init() the default "iomem_resource" will be used. Update the arguments list of allocate_resource() in fill_list() to always allocate a region from the hotpluggable range (maximum possible addressable physical memory range for which the linear mapping could be created). If arch doesn't define arch_get_mappable_range() the default range (0,-1) will be used. The behaviour on x86 won't be changed by current patch as both arch_xen_unpopulated_init() and arch_get_mappable_range() are not implemented for it. Also fallback to allocate xenballooned pages (balloon out RAM pages) if we do not have any suitable resource to work with (target_resource is invalid) and as the result we won't be able to provide unpopulated pages on a request. Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Link: https://lore.kernel.org/r/1639080336-26573-5-git-send-email-olekstysh@gmail.com Signed-off-by: Juergen Gross <jgross@suse.com>
74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _XEN_XEN_H
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#define _XEN_XEN_H
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enum xen_domain_type {
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XEN_NATIVE, /* running on bare hardware */
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XEN_PV_DOMAIN, /* running in a PV domain */
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XEN_HVM_DOMAIN, /* running in a Xen hvm domain */
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};
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#ifdef CONFIG_XEN
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extern enum xen_domain_type xen_domain_type;
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#else
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#define xen_domain_type XEN_NATIVE
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#endif
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#ifdef CONFIG_XEN_PVH
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extern bool xen_pvh;
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#else
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#define xen_pvh 0
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#endif
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#define xen_domain() (xen_domain_type != XEN_NATIVE)
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#define xen_pv_domain() (xen_domain_type == XEN_PV_DOMAIN)
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#define xen_hvm_domain() (xen_domain_type == XEN_HVM_DOMAIN)
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#define xen_pvh_domain() (xen_pvh)
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#include <linux/types.h>
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extern uint32_t xen_start_flags;
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#include <xen/interface/hvm/start_info.h>
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extern struct hvm_start_info pvh_start_info;
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#ifdef CONFIG_XEN_DOM0
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#include <xen/interface/xen.h>
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#include <asm/xen/hypervisor.h>
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#define xen_initial_domain() (xen_domain() && \
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(xen_start_flags & SIF_INITDOMAIN))
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#else /* !CONFIG_XEN_DOM0 */
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#define xen_initial_domain() (0)
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#endif /* CONFIG_XEN_DOM0 */
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struct bio_vec;
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struct page;
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bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
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const struct page *page);
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#if defined(CONFIG_MEMORY_HOTPLUG) && defined(CONFIG_XEN_BALLOON)
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extern u64 xen_saved_max_mem_size;
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#endif
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#ifdef CONFIG_XEN_UNPOPULATED_ALLOC
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int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages);
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void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages);
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#include <linux/ioport.h>
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int arch_xen_unpopulated_init(struct resource **res);
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#else
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#include <xen/balloon.h>
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static inline int xen_alloc_unpopulated_pages(unsigned int nr_pages,
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struct page **pages)
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{
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return xen_alloc_ballooned_pages(nr_pages, pages);
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}
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static inline void xen_free_unpopulated_pages(unsigned int nr_pages,
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struct page **pages)
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{
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xen_free_ballooned_pages(nr_pages, pages);
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}
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#endif
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#endif /* _XEN_XEN_H */
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