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Code Issues Releases Activity

XEN/amd64 may initiate i/o over the pages not mapped by the direct

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map.  Handle busdma bouncing and ata PIO accesses by using global
frame used by the current CPU locally for the duration of
pmap_quick_enter/remove_page().  A spin mutex protects the concurent
frame use and prevents thread migration.

Noted by:	royger
Reviewed by:	alc, jah, royger (previous version)
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Konstantin Belousov 2015-08-17 18:42:45 +00:00
parent 9b0ffde9e8
commit 7a39d38dbd
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=286855
1 changed files with 24 additions and 2 deletions
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26
sys/amd64/amd64/pmap.c
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@ -390,6 +390,8 @@ static struct md_page *pv_table;
*/
pt_entry_t *CMAP1 = 0;
caddr_t CADDR1 = 0;
static vm_offset_t qframe = 0;
static struct mtx qframe_mtx;
static int pmap_flags = PMAP_PDE_SUPERPAGE; /* flags for x86 pmaps */
@ -1031,7 +1033,7 @@ pmap_init(void)
struct pmap_preinit_mapping *ppim;
vm_page_t mpte;
vm_size_t s;
int i, pv_npg;
int error, i, pv_npg;
/*
* Initialize the vm page array entries for the kernel pmap's
@ -1112,6 +1114,12 @@ pmap_init(void)
printf("PPIM %u: PA=%#lx, VA=%#lx, size=%#lx, mode=%#x\n", i,
ppim->pa, ppim->va, ppim->sz, ppim->mode);
}
mtx_init(&qframe_mtx, "qfrmlk", NULL, MTX_SPIN);
error = vmem_alloc(kernel_arena, PAGE_SIZE, M_BESTFIT | M_WAITOK,
(vmem_addr_t *)&qframe);
if (error != 0)
panic("qframe allocation failed");
}
static SYSCTL_NODE(_vm_pmap, OID_AUTO, pde, CTLFLAG_RD, 0,
@ -7019,13 +7027,27 @@ pmap_unmap_io_transient(vm_page_t page[], vm_offset_t vaddr[], int count,
vm_offset_t
pmap_quick_enter_page(vm_page_t m)
{
vm_paddr_t paddr;
return (PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m)));
paddr = VM_PAGE_TO_PHYS(m);
if (paddr < dmaplimit)
return (PHYS_TO_DMAP(paddr));
mtx_lock_spin(&qframe_mtx);
KASSERT(*vtopte(qframe) == 0, ("qframe busy"));
pte_store(vtopte(qframe), paddr | X86_PG_RW | X86_PG_V | X86_PG_A |
X86_PG_M | pmap_cache_bits(kernel_pmap, m->md.pat_mode, 0));
return (qframe);
}
void
pmap_quick_remove_page(vm_offset_t addr)
{
if (addr != qframe)
return;
pte_store(vtopte(qframe), 0);
invlpg(qframe);
mtx_unlock_spin(&qframe_mtx);
}
#include "opt_ddb.h"