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Map the vm_page array into KVA on amd64.

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r351198 allows the kernel to use domain-local memory to back the vm_page
array (up to 2MB boundaries) and reserves a separate PML4 entry for that
purpose.  One consequence of that change is that the vm_page array is no
longer present in minidumps, which only adds pages mapped above
VM_MIN_KERNEL_ADDRESS.

To avoid the friction caused by having kernel data structures mapped
below VM_MIN_KERNEL_ADDRESS, map the vm_page array starting at
VM_MIN_KERNEL_ADDRESS instead of using a dedicated PML4 entry.

Reviewed by:	kib
Discussed with:	jeff
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D21491
This commit is contained in:
Mark Johnston 2019-09-03 13:18:51 +00:00
parent f5791174df
commit 9d75f0dc75
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=351742
4 changed files with 27 additions and 40 deletions
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38
sys/amd64/amd64/pmap.c
View File

@ -384,9 +384,6 @@ static u_int64_t DMPDphys; /* phys addr of direct mapped level 2 */
static u_int64_t DMPDPphys; /* phys addr of direct mapped level 3 */
static int ndmpdpphys; /* number of DMPDPphys pages */
static uint64_t PAPDPphys; /* phys addr of page array level 3 */
static int npapdpphys; /* number of PAPDPphys pages */
static vm_paddr_t KERNend; /* phys addr of end of bootstrap data */
/*
@ -1431,16 +1428,6 @@ create_pagetables(vm_paddr_t *firstaddr)
pml4_entry_t *p4_p;
uint64_t DMPDkernphys;
npapdpphys = howmany(ptoa(Maxmem) / sizeof(struct vm_page), NBPML4);
if (npapdpphys > NPAPML4E) {
printf("NDMPML4E limits system to %lu GB\n",
(NDMPML4E * 512) * (PAGE_SIZE / sizeof(struct vm_page)));
npapdpphys = NPAPML4E;
Maxmem = atop(NPAPML4E * NBPML4 *
(PAGE_SIZE / sizeof(struct vm_page)));
}
PAPDPphys = allocpages(firstaddr, npapdpphys);
/* Allocate page table pages for the direct map */
ndmpdp = howmany(ptoa(Maxmem), NBPDP);
if (ndmpdp < 4) /* Minimum 4GB of dirmap */
@ -1587,12 +1574,6 @@ create_pagetables(vm_paddr_t *firstaddr)
p4_p[KPML4BASE + i] = KPDPphys + ptoa(i);
p4_p[KPML4BASE + i] |= X86_PG_RW | X86_PG_V;
}
/* Connect the page array slots up to the pml4. */
for (i = 0; i < npapdpphys; i++) {
p4_p[PAPML4I + i] = PAPDPphys + ptoa(i);
p4_p[PAPML4I + i] |= X86_PG_RW | X86_PG_V | pg_nx;
}
}
/*
@ -3456,11 +3437,6 @@ pmap_pinit_pml4(vm_page_t pml4pg)
X86_PG_V;
}
for (i = 0; i < npapdpphys; i++) {
pm_pml4[PAPML4I + i] = (PAPDPphys + ptoa(i)) | X86_PG_RW |
X86_PG_V;
}
/* install self-referential address mapping entry(s) */
pm_pml4[PML4PML4I] = VM_PAGE_TO_PHYS(pml4pg) | X86_PG_V | X86_PG_RW |
X86_PG_A | X86_PG_M;
@ -3817,8 +3793,6 @@ pmap_release(pmap_t pmap)
pmap->pm_pml4[KPML4BASE + i] = 0;
for (i = 0; i < ndmpdpphys; i++)/* Direct Map */
pmap->pm_pml4[DMPML4I + i] = 0;
for (i = 0; i < npapdpphys; i++)
pmap->pm_pml4[PAPML4I + i] = 0;
pmap->pm_pml4[PML4PML4I] = 0; /* Recursive Mapping */
for (i = 0; i < lm_ents; i++) /* Large Map */
pmap->pm_pml4[LMSPML4I + i] = 0;
@ -3856,6 +3830,10 @@ kvm_free(SYSCTL_HANDLER_ARGS)
SYSCTL_PROC(_vm, OID_AUTO, kvm_free, CTLTYPE_LONG|CTLFLAG_RD,
0, 0, kvm_free, "LU", "Amount of KVM free");
/*
* Allocate physical memory for the vm_page array and map it into KVA,
* attempting to back the vm_pages with domain-local memory.
*/
void
pmap_page_array_startup(long pages)
{
@ -3868,14 +3846,15 @@ pmap_page_array_startup(long pages)
vm_page_array_size = pages;
start = va = PA_MIN_ADDRESS;
end = va + (pages * sizeof(struct vm_page));
start = va = VM_MIN_KERNEL_ADDRESS;
end = va + pages * sizeof(struct vm_page);
while (va < end) {
pfn = first_page + ((va - start) / sizeof(struct vm_page));
pfn = first_page + (va - start) / sizeof(struct vm_page);
domain = _vm_phys_domain(ctob(pfn));
pdpe = pmap_pdpe(kernel_pmap, va);
if ((*pdpe & X86_PG_V) == 0) {
pa = vm_phys_early_alloc(domain, PAGE_SIZE);
dump_add_page(pa);
bzero((void *)PHYS_TO_DMAP(pa), PAGE_SIZE);
*pdpe = (pdp_entry_t)(pa | X86_PG_V | X86_PG_RW |
X86_PG_A | X86_PG_M);
@ -3892,6 +3871,7 @@ pmap_page_array_startup(long pages)
pde_store(pde, newpdir);
va += NBPDR;
}
vm_page_array = (vm_page_t)start;
}
/*

11
sys/amd64/include/vmparam.h
View File

@ -160,13 +160,12 @@
* 0xffff808000000000 - 0xffff847fffffffff large map (can be tuned up)
* 0xffff848000000000 - 0xfffff7ffffffffff unused (large map extends there)
* 0xfffff80000000000 - 0xfffffbffffffffff 4TB direct map
* 0xfffffc0000000000 - 0xfffffcffffffffff unused
* 0xfffffd0000000000 - 0xfffffd7fffffffff page array 512GB
* 0xfffffd8000000000 - 0xfffffdffffffffff unused
* 0xfffffc0000000000 - 0xfffffdffffffffff unused
* 0xfffffe0000000000 - 0xffffffffffffffff 2TB kernel map
*
* Within the kernel map:
*
* 0xfffffe0000000000 vm_page_array
* 0xffffffff80000000 KERNBASE
*/
@ -216,10 +215,10 @@
(x) & ~DMAP_MIN_ADDRESS; })
/*
* amd64 statically allocates the page array address so that it can
* be more easily allocated on the correct memory domains.
* amd64 maps the page array into KVA so that it can be more easily
* allocated on the correct memory domains.
*/
#define PMAP_HAS_PAGE_ARRAY 1
#define PMAP_HAS_PAGE_ARRAY 1
/*
* How many physical pages per kmem arena virtual page.

14
sys/vm/vm_kern.c
View File

@ -759,7 +759,7 @@ kmem_init(vm_offset_t start, vm_offset_t end)
vm_map_lock(m);
/* N.B.: cannot use kgdb to debug, starting with this assignment ... */
kernel_map = m;
(void) vm_map_insert(m, NULL, (vm_ooffset_t) 0,
(void)vm_map_insert(m, NULL, 0,
#ifdef __amd64__
KERNBASE,
#else
@ -767,6 +767,18 @@ kmem_init(vm_offset_t start, vm_offset_t end)
#endif
start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
/* ... and ending with the completion of the above `insert' */
#ifdef __amd64__
/*
* Mark KVA used for the page array as allocated. Other platforms
* that handle vm_page_array allocation can simply adjust virtual_avail
* instead.
*/
(void)vm_map_insert(m, NULL, 0, (vm_offset_t)vm_page_array,
(vm_offset_t)vm_page_array + round_2mpage(vm_page_array_size *
sizeof(struct vm_page)),
VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT);
#endif
vm_map_unlock(m);
/*

4
sys/vm/vm_page.c
View File

@ -135,11 +135,7 @@ static int vm_pageproc_waiters;
*/
vm_page_t bogus_page;
#ifdef PMAP_HAS_PAGE_ARRAY
vm_page_t vm_page_array = (vm_page_t)PA_MIN_ADDRESS;
#else
vm_page_t vm_page_array;
#endif
long vm_page_array_size;
long first_page;