mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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1a781a777b
Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
837 lines
20 KiB
C
837 lines
20 KiB
C
/*
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* Xen mmu operations
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*
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* This file contains the various mmu fetch and update operations.
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* The most important job they must perform is the mapping between the
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* domain's pfn and the overall machine mfns.
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*
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* Xen allows guests to directly update the pagetable, in a controlled
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* fashion. In other words, the guest modifies the same pagetable
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* that the CPU actually uses, which eliminates the overhead of having
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* a separate shadow pagetable.
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*
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* In order to allow this, it falls on the guest domain to map its
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* notion of a "physical" pfn - which is just a domain-local linear
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* address - into a real "machine address" which the CPU's MMU can
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* use.
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*
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* A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
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* inserted directly into the pagetable. When creating a new
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* pte/pmd/pgd, it converts the passed pfn into an mfn. Conversely,
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* when reading the content back with __(pgd|pmd|pte)_val, it converts
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* the mfn back into a pfn.
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*
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* The other constraint is that all pages which make up a pagetable
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* must be mapped read-only in the guest. This prevents uncontrolled
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* guest updates to the pagetable. Xen strictly enforces this, and
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* will disallow any pagetable update which will end up mapping a
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* pagetable page RW, and will disallow using any writable page as a
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* pagetable.
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*
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* Naively, when loading %cr3 with the base of a new pagetable, Xen
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* would need to validate the whole pagetable before going on.
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* Naturally, this is quite slow. The solution is to "pin" a
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* pagetable, which enforces all the constraints on the pagetable even
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* when it is not actively in use. This menas that Xen can be assured
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* that it is still valid when you do load it into %cr3, and doesn't
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* need to revalidate it.
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*
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* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
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*/
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#include <linux/sched.h>
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#include <linux/highmem.h>
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#include <linux/bug.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include <asm/paravirt.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/page.h>
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#include <xen/interface/xen.h>
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#include "multicalls.h"
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#include "mmu.h"
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#define P2M_ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
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#define TOP_ENTRIES (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)
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/* Placeholder for holes in the address space */
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static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE]
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__attribute__((section(".data.page_aligned"))) =
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{ [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
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/* Array of pointers to pages containing p2m entries */
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static unsigned long *p2m_top[TOP_ENTRIES]
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__attribute__((section(".data.page_aligned"))) =
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{ [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
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/* Arrays of p2m arrays expressed in mfns used for save/restore */
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static unsigned long p2m_top_mfn[TOP_ENTRIES]
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__attribute__((section(".bss.page_aligned")));
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static unsigned long p2m_top_mfn_list[
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PAGE_ALIGN(TOP_ENTRIES / P2M_ENTRIES_PER_PAGE)]
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__attribute__((section(".bss.page_aligned")));
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static inline unsigned p2m_top_index(unsigned long pfn)
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{
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BUG_ON(pfn >= MAX_DOMAIN_PAGES);
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return pfn / P2M_ENTRIES_PER_PAGE;
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}
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static inline unsigned p2m_index(unsigned long pfn)
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{
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return pfn % P2M_ENTRIES_PER_PAGE;
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}
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/* Build the parallel p2m_top_mfn structures */
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void xen_setup_mfn_list_list(void)
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{
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unsigned pfn, idx;
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for(pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_ENTRIES_PER_PAGE) {
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unsigned topidx = p2m_top_index(pfn);
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p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
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}
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for(idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
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unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
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p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
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}
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BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
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HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
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virt_to_mfn(p2m_top_mfn_list);
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HYPERVISOR_shared_info->arch.max_pfn = xen_start_info->nr_pages;
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}
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/* Set up p2m_top to point to the domain-builder provided p2m pages */
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void __init xen_build_dynamic_phys_to_machine(void)
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{
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unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
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unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
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unsigned pfn;
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for(pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
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unsigned topidx = p2m_top_index(pfn);
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p2m_top[topidx] = &mfn_list[pfn];
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}
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}
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unsigned long get_phys_to_machine(unsigned long pfn)
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{
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unsigned topidx, idx;
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if (unlikely(pfn >= MAX_DOMAIN_PAGES))
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return INVALID_P2M_ENTRY;
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topidx = p2m_top_index(pfn);
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idx = p2m_index(pfn);
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return p2m_top[topidx][idx];
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}
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EXPORT_SYMBOL_GPL(get_phys_to_machine);
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static void alloc_p2m(unsigned long **pp, unsigned long *mfnp)
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{
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unsigned long *p;
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unsigned i;
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p = (void *)__get_free_page(GFP_KERNEL | __GFP_NOFAIL);
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BUG_ON(p == NULL);
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for(i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
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p[i] = INVALID_P2M_ENTRY;
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if (cmpxchg(pp, p2m_missing, p) != p2m_missing)
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free_page((unsigned long)p);
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else
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*mfnp = virt_to_mfn(p);
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}
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void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
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{
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unsigned topidx, idx;
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if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
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BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
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return;
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}
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if (unlikely(pfn >= MAX_DOMAIN_PAGES)) {
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BUG_ON(mfn != INVALID_P2M_ENTRY);
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return;
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}
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topidx = p2m_top_index(pfn);
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if (p2m_top[topidx] == p2m_missing) {
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/* no need to allocate a page to store an invalid entry */
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if (mfn == INVALID_P2M_ENTRY)
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return;
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alloc_p2m(&p2m_top[topidx], &p2m_top_mfn[topidx]);
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}
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idx = p2m_index(pfn);
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p2m_top[topidx][idx] = mfn;
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}
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xmaddr_t arbitrary_virt_to_machine(unsigned long address)
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{
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unsigned int level;
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pte_t *pte = lookup_address(address, &level);
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unsigned offset = address & ~PAGE_MASK;
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BUG_ON(pte == NULL);
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return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset);
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}
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void make_lowmem_page_readonly(void *vaddr)
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{
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pte_t *pte, ptev;
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unsigned long address = (unsigned long)vaddr;
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unsigned int level;
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pte = lookup_address(address, &level);
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BUG_ON(pte == NULL);
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ptev = pte_wrprotect(*pte);
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if (HYPERVISOR_update_va_mapping(address, ptev, 0))
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BUG();
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}
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void make_lowmem_page_readwrite(void *vaddr)
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{
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pte_t *pte, ptev;
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unsigned long address = (unsigned long)vaddr;
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unsigned int level;
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pte = lookup_address(address, &level);
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BUG_ON(pte == NULL);
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ptev = pte_mkwrite(*pte);
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if (HYPERVISOR_update_va_mapping(address, ptev, 0))
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BUG();
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}
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static bool page_pinned(void *ptr)
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{
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struct page *page = virt_to_page(ptr);
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return PagePinned(page);
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}
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static void extend_mmu_update(const struct mmu_update *update)
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{
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struct multicall_space mcs;
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struct mmu_update *u;
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mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
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if (mcs.mc != NULL)
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mcs.mc->args[1]++;
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else {
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mcs = __xen_mc_entry(sizeof(*u));
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MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
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}
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u = mcs.args;
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*u = *update;
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}
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void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
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{
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struct mmu_update u;
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preempt_disable();
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xen_mc_batch();
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u.ptr = virt_to_machine(ptr).maddr;
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u.val = pmd_val_ma(val);
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extend_mmu_update(&u);
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xen_mc_issue(PARAVIRT_LAZY_MMU);
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preempt_enable();
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}
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void xen_set_pmd(pmd_t *ptr, pmd_t val)
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{
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/* If page is not pinned, we can just update the entry
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directly */
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if (!page_pinned(ptr)) {
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*ptr = val;
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return;
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}
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xen_set_pmd_hyper(ptr, val);
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}
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/*
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* Associate a virtual page frame with a given physical page frame
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* and protection flags for that frame.
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*/
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void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = swapper_pg_dir + pgd_index(vaddr);
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if (pgd_none(*pgd)) {
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BUG();
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return;
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}
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pud = pud_offset(pgd, vaddr);
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if (pud_none(*pud)) {
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BUG();
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return;
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}
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pmd = pmd_offset(pud, vaddr);
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if (pmd_none(*pmd)) {
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BUG();
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return;
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}
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pte = pte_offset_kernel(pmd, vaddr);
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/* <mfn,flags> stored as-is, to permit clearing entries */
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xen_set_pte(pte, mfn_pte(mfn, flags));
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/*
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* It's enough to flush this one mapping.
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* (PGE mappings get flushed as well)
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*/
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__flush_tlb_one(vaddr);
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}
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void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pteval)
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{
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/* updates to init_mm may be done without lock */
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if (mm == &init_mm)
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preempt_disable();
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if (mm == current->mm || mm == &init_mm) {
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if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
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struct multicall_space mcs;
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mcs = xen_mc_entry(0);
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MULTI_update_va_mapping(mcs.mc, addr, pteval, 0);
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xen_mc_issue(PARAVIRT_LAZY_MMU);
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goto out;
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} else
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if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0)
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goto out;
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}
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xen_set_pte(ptep, pteval);
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out:
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if (mm == &init_mm)
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preempt_enable();
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}
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pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
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{
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/* Just return the pte as-is. We preserve the bits on commit */
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return *ptep;
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}
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void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte)
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{
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struct mmu_update u;
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xen_mc_batch();
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u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
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u.val = pte_val_ma(pte);
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extend_mmu_update(&u);
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xen_mc_issue(PARAVIRT_LAZY_MMU);
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}
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/* Assume pteval_t is equivalent to all the other *val_t types. */
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static pteval_t pte_mfn_to_pfn(pteval_t val)
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{
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if (val & _PAGE_PRESENT) {
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unsigned long mfn = (val & PTE_MASK) >> PAGE_SHIFT;
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pteval_t flags = val & ~PTE_MASK;
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val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
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}
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return val;
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}
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static pteval_t pte_pfn_to_mfn(pteval_t val)
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{
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if (val & _PAGE_PRESENT) {
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unsigned long pfn = (val & PTE_MASK) >> PAGE_SHIFT;
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pteval_t flags = val & ~PTE_MASK;
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val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags;
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}
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return val;
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}
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pteval_t xen_pte_val(pte_t pte)
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{
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return pte_mfn_to_pfn(pte.pte);
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}
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pgdval_t xen_pgd_val(pgd_t pgd)
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{
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return pte_mfn_to_pfn(pgd.pgd);
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}
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pte_t xen_make_pte(pteval_t pte)
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{
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pte = pte_pfn_to_mfn(pte);
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return native_make_pte(pte);
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}
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|
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pgd_t xen_make_pgd(pgdval_t pgd)
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{
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pgd = pte_pfn_to_mfn(pgd);
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return native_make_pgd(pgd);
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}
|
|
|
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pmdval_t xen_pmd_val(pmd_t pmd)
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{
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return pte_mfn_to_pfn(pmd.pmd);
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}
|
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|
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void xen_set_pud_hyper(pud_t *ptr, pud_t val)
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{
|
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struct mmu_update u;
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|
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preempt_disable();
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|
|
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xen_mc_batch();
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|
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u.ptr = virt_to_machine(ptr).maddr;
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u.val = pud_val_ma(val);
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extend_mmu_update(&u);
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|
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xen_mc_issue(PARAVIRT_LAZY_MMU);
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|
|
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preempt_enable();
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}
|
|
|
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void xen_set_pud(pud_t *ptr, pud_t val)
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{
|
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/* If page is not pinned, we can just update the entry
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directly */
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if (!page_pinned(ptr)) {
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*ptr = val;
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return;
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}
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|
|
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xen_set_pud_hyper(ptr, val);
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}
|
|
|
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void xen_set_pte(pte_t *ptep, pte_t pte)
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{
|
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ptep->pte_high = pte.pte_high;
|
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smp_wmb();
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ptep->pte_low = pte.pte_low;
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}
|
|
|
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void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
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{
|
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set_64bit((u64 *)ptep, pte_val_ma(pte));
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}
|
|
|
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void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
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{
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ptep->pte_low = 0;
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smp_wmb(); /* make sure low gets written first */
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ptep->pte_high = 0;
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}
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|
|
|
void xen_pmd_clear(pmd_t *pmdp)
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{
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set_pmd(pmdp, __pmd(0));
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}
|
|
|
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pmd_t xen_make_pmd(pmdval_t pmd)
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{
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pmd = pte_pfn_to_mfn(pmd);
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return native_make_pmd(pmd);
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}
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|
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/*
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(Yet another) pagetable walker. This one is intended for pinning a
|
|
pagetable. This means that it walks a pagetable and calls the
|
|
callback function on each page it finds making up the page table,
|
|
at every level. It walks the entire pagetable, but it only bothers
|
|
pinning pte pages which are below pte_limit. In the normal case
|
|
this will be TASK_SIZE, but at boot we need to pin up to
|
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FIXADDR_TOP. But the important bit is that we don't pin beyond
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there, because then we start getting into Xen's ptes.
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|
*/
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|
static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, enum pt_level),
|
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unsigned long limit)
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{
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pgd_t *pgd = pgd_base;
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|
int flush = 0;
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|
unsigned long addr = 0;
|
|
unsigned long pgd_next;
|
|
|
|
BUG_ON(limit > FIXADDR_TOP);
|
|
|
|
if (xen_feature(XENFEAT_auto_translated_physmap))
|
|
return 0;
|
|
|
|
for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) {
|
|
pud_t *pud;
|
|
unsigned long pud_limit, pud_next;
|
|
|
|
pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP);
|
|
|
|
if (!pgd_val(*pgd))
|
|
continue;
|
|
|
|
pud = pud_offset(pgd, 0);
|
|
|
|
if (PTRS_PER_PUD > 1) /* not folded */
|
|
flush |= (*func)(virt_to_page(pud), PT_PUD);
|
|
|
|
for (; addr != pud_limit; pud++, addr = pud_next) {
|
|
pmd_t *pmd;
|
|
unsigned long pmd_limit;
|
|
|
|
pud_next = pud_addr_end(addr, pud_limit);
|
|
|
|
if (pud_next < limit)
|
|
pmd_limit = pud_next;
|
|
else
|
|
pmd_limit = limit;
|
|
|
|
if (pud_none(*pud))
|
|
continue;
|
|
|
|
pmd = pmd_offset(pud, 0);
|
|
|
|
if (PTRS_PER_PMD > 1) /* not folded */
|
|
flush |= (*func)(virt_to_page(pmd), PT_PMD);
|
|
|
|
for (; addr != pmd_limit; pmd++) {
|
|
addr += (PAGE_SIZE * PTRS_PER_PTE);
|
|
if ((pmd_limit-1) < (addr-1)) {
|
|
addr = pmd_limit;
|
|
break;
|
|
}
|
|
|
|
if (pmd_none(*pmd))
|
|
continue;
|
|
|
|
flush |= (*func)(pmd_page(*pmd), PT_PTE);
|
|
}
|
|
}
|
|
}
|
|
|
|
flush |= (*func)(virt_to_page(pgd_base), PT_PGD);
|
|
|
|
return flush;
|
|
}
|
|
|
|
static spinlock_t *lock_pte(struct page *page)
|
|
{
|
|
spinlock_t *ptl = NULL;
|
|
|
|
#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
|
|
ptl = __pte_lockptr(page);
|
|
spin_lock(ptl);
|
|
#endif
|
|
|
|
return ptl;
|
|
}
|
|
|
|
static void do_unlock(void *v)
|
|
{
|
|
spinlock_t *ptl = v;
|
|
spin_unlock(ptl);
|
|
}
|
|
|
|
static void xen_do_pin(unsigned level, unsigned long pfn)
|
|
{
|
|
struct mmuext_op *op;
|
|
struct multicall_space mcs;
|
|
|
|
mcs = __xen_mc_entry(sizeof(*op));
|
|
op = mcs.args;
|
|
op->cmd = level;
|
|
op->arg1.mfn = pfn_to_mfn(pfn);
|
|
MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
|
|
}
|
|
|
|
static int pin_page(struct page *page, enum pt_level level)
|
|
{
|
|
unsigned pgfl = TestSetPagePinned(page);
|
|
int flush;
|
|
|
|
if (pgfl)
|
|
flush = 0; /* already pinned */
|
|
else if (PageHighMem(page))
|
|
/* kmaps need flushing if we found an unpinned
|
|
highpage */
|
|
flush = 1;
|
|
else {
|
|
void *pt = lowmem_page_address(page);
|
|
unsigned long pfn = page_to_pfn(page);
|
|
struct multicall_space mcs = __xen_mc_entry(0);
|
|
spinlock_t *ptl;
|
|
|
|
flush = 0;
|
|
|
|
ptl = NULL;
|
|
if (level == PT_PTE)
|
|
ptl = lock_pte(page);
|
|
|
|
MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
|
|
pfn_pte(pfn, PAGE_KERNEL_RO),
|
|
level == PT_PGD ? UVMF_TLB_FLUSH : 0);
|
|
|
|
if (level == PT_PTE)
|
|
xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
|
|
|
|
if (ptl) {
|
|
/* Queue a deferred unlock for when this batch
|
|
is completed. */
|
|
xen_mc_callback(do_unlock, ptl);
|
|
}
|
|
}
|
|
|
|
return flush;
|
|
}
|
|
|
|
/* This is called just after a mm has been created, but it has not
|
|
been used yet. We need to make sure that its pagetable is all
|
|
read-only, and can be pinned. */
|
|
void xen_pgd_pin(pgd_t *pgd)
|
|
{
|
|
xen_mc_batch();
|
|
|
|
if (pgd_walk(pgd, pin_page, TASK_SIZE)) {
|
|
/* re-enable interrupts for kmap_flush_unused */
|
|
xen_mc_issue(0);
|
|
kmap_flush_unused();
|
|
xen_mc_batch();
|
|
}
|
|
|
|
xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
|
|
xen_mc_issue(0);
|
|
}
|
|
|
|
/*
|
|
* On save, we need to pin all pagetables to make sure they get their
|
|
* mfns turned into pfns. Search the list for any unpinned pgds and pin
|
|
* them (unpinned pgds are not currently in use, probably because the
|
|
* process is under construction or destruction).
|
|
*/
|
|
void xen_mm_pin_all(void)
|
|
{
|
|
unsigned long flags;
|
|
struct page *page;
|
|
|
|
spin_lock_irqsave(&pgd_lock, flags);
|
|
|
|
list_for_each_entry(page, &pgd_list, lru) {
|
|
if (!PagePinned(page)) {
|
|
xen_pgd_pin((pgd_t *)page_address(page));
|
|
SetPageSavePinned(page);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pgd_lock, flags);
|
|
}
|
|
|
|
/* The init_mm pagetable is really pinned as soon as its created, but
|
|
that's before we have page structures to store the bits. So do all
|
|
the book-keeping now. */
|
|
static __init int mark_pinned(struct page *page, enum pt_level level)
|
|
{
|
|
SetPagePinned(page);
|
|
return 0;
|
|
}
|
|
|
|
void __init xen_mark_init_mm_pinned(void)
|
|
{
|
|
pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP);
|
|
}
|
|
|
|
static int unpin_page(struct page *page, enum pt_level level)
|
|
{
|
|
unsigned pgfl = TestClearPagePinned(page);
|
|
|
|
if (pgfl && !PageHighMem(page)) {
|
|
void *pt = lowmem_page_address(page);
|
|
unsigned long pfn = page_to_pfn(page);
|
|
spinlock_t *ptl = NULL;
|
|
struct multicall_space mcs;
|
|
|
|
if (level == PT_PTE) {
|
|
ptl = lock_pte(page);
|
|
|
|
xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
|
|
}
|
|
|
|
mcs = __xen_mc_entry(0);
|
|
|
|
MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
|
|
pfn_pte(pfn, PAGE_KERNEL),
|
|
level == PT_PGD ? UVMF_TLB_FLUSH : 0);
|
|
|
|
if (ptl) {
|
|
/* unlock when batch completed */
|
|
xen_mc_callback(do_unlock, ptl);
|
|
}
|
|
}
|
|
|
|
return 0; /* never need to flush on unpin */
|
|
}
|
|
|
|
/* Release a pagetables pages back as normal RW */
|
|
static void xen_pgd_unpin(pgd_t *pgd)
|
|
{
|
|
xen_mc_batch();
|
|
|
|
xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
|
|
|
|
pgd_walk(pgd, unpin_page, TASK_SIZE);
|
|
|
|
xen_mc_issue(0);
|
|
}
|
|
|
|
/*
|
|
* On resume, undo any pinning done at save, so that the rest of the
|
|
* kernel doesn't see any unexpected pinned pagetables.
|
|
*/
|
|
void xen_mm_unpin_all(void)
|
|
{
|
|
unsigned long flags;
|
|
struct page *page;
|
|
|
|
spin_lock_irqsave(&pgd_lock, flags);
|
|
|
|
list_for_each_entry(page, &pgd_list, lru) {
|
|
if (PageSavePinned(page)) {
|
|
BUG_ON(!PagePinned(page));
|
|
printk("unpinning pinned %p\n", page_address(page));
|
|
xen_pgd_unpin((pgd_t *)page_address(page));
|
|
ClearPageSavePinned(page);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pgd_lock, flags);
|
|
}
|
|
|
|
void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
|
|
{
|
|
spin_lock(&next->page_table_lock);
|
|
xen_pgd_pin(next->pgd);
|
|
spin_unlock(&next->page_table_lock);
|
|
}
|
|
|
|
void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
|
|
{
|
|
spin_lock(&mm->page_table_lock);
|
|
xen_pgd_pin(mm->pgd);
|
|
spin_unlock(&mm->page_table_lock);
|
|
}
|
|
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* Another cpu may still have their %cr3 pointing at the pagetable, so
|
|
we need to repoint it somewhere else before we can unpin it. */
|
|
static void drop_other_mm_ref(void *info)
|
|
{
|
|
struct mm_struct *mm = info;
|
|
|
|
if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
|
|
leave_mm(smp_processor_id());
|
|
|
|
/* If this cpu still has a stale cr3 reference, then make sure
|
|
it has been flushed. */
|
|
if (x86_read_percpu(xen_current_cr3) == __pa(mm->pgd)) {
|
|
load_cr3(swapper_pg_dir);
|
|
arch_flush_lazy_cpu_mode();
|
|
}
|
|
}
|
|
|
|
static void drop_mm_ref(struct mm_struct *mm)
|
|
{
|
|
cpumask_t mask;
|
|
unsigned cpu;
|
|
|
|
if (current->active_mm == mm) {
|
|
if (current->mm == mm)
|
|
load_cr3(swapper_pg_dir);
|
|
else
|
|
leave_mm(smp_processor_id());
|
|
arch_flush_lazy_cpu_mode();
|
|
}
|
|
|
|
/* Get the "official" set of cpus referring to our pagetable. */
|
|
mask = mm->cpu_vm_mask;
|
|
|
|
/* It's possible that a vcpu may have a stale reference to our
|
|
cr3, because its in lazy mode, and it hasn't yet flushed
|
|
its set of pending hypercalls yet. In this case, we can
|
|
look at its actual current cr3 value, and force it to flush
|
|
if needed. */
|
|
for_each_online_cpu(cpu) {
|
|
if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
|
|
cpu_set(cpu, mask);
|
|
}
|
|
|
|
if (!cpus_empty(mask))
|
|
smp_call_function_mask(mask, drop_other_mm_ref, mm, 1);
|
|
}
|
|
#else
|
|
static void drop_mm_ref(struct mm_struct *mm)
|
|
{
|
|
if (current->active_mm == mm)
|
|
load_cr3(swapper_pg_dir);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* While a process runs, Xen pins its pagetables, which means that the
|
|
* hypervisor forces it to be read-only, and it controls all updates
|
|
* to it. This means that all pagetable updates have to go via the
|
|
* hypervisor, which is moderately expensive.
|
|
*
|
|
* Since we're pulling the pagetable down, we switch to use init_mm,
|
|
* unpin old process pagetable and mark it all read-write, which
|
|
* allows further operations on it to be simple memory accesses.
|
|
*
|
|
* The only subtle point is that another CPU may be still using the
|
|
* pagetable because of lazy tlb flushing. This means we need need to
|
|
* switch all CPUs off this pagetable before we can unpin it.
|
|
*/
|
|
void xen_exit_mmap(struct mm_struct *mm)
|
|
{
|
|
get_cpu(); /* make sure we don't move around */
|
|
drop_mm_ref(mm);
|
|
put_cpu();
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
|
|
/* pgd may not be pinned in the error exit path of execve */
|
|
if (page_pinned(mm->pgd))
|
|
xen_pgd_unpin(mm->pgd);
|
|
|
|
spin_unlock(&mm->page_table_lock);
|
|
}
|