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riscv: Maintain the allpmaps list only in SV39 mode

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When four-level page tables are used, there is no need to distribute
updates to the top-level page to all pmaps.

Reviewed by:	jhb
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D34277
This commit is contained in:
Mark Johnston 2022-03-01 09:06:31 -05:00
parent 5cf3a8216e
commit ceed61483c
1 changed files with 31 additions and 17 deletions
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48
sys/riscv/riscv/pmap.c
View file

@ -486,8 +486,13 @@ pmap_distribute_l1(struct pmap *pmap, vm_pindex_t l1index,
struct pmap *user_pmap;
pd_entry_t *l1;
/* Distribute new kernel L1 entry to all the user pmaps */
if (pmap != kernel_pmap)
/*
* Distribute new kernel L1 entry to all the user pmaps. This is only
* necessary with three-level paging configured: with four-level paging
* the kernel's half of the top-level page table page is static and can
* simply be copied at pmap initialization time.
*/
if (pmap != kernel_pmap || pmap_mode != PMAP_MODE_SV39)
return;
mtx_lock(&allpmaps_lock);
@ -1266,6 +1271,7 @@ pmap_pinit(pmap_t pmap)
{
vm_paddr_t topphys;
vm_page_t mtop;
size_t i;
mtop = vm_page_alloc_noobj(VM_ALLOC_WIRED | VM_ALLOC_ZERO |
VM_ALLOC_WAITOK);
@ -1278,19 +1284,25 @@ pmap_pinit(pmap_t pmap)
CPU_ZERO(&pmap->pm_active);
/*
* Copy L1 entries from the kernel pmap. This must be done with the
* allpmaps lock held to avoid races with pmap_distribute_l1().
*/
mtx_lock(&allpmaps_lock);
LIST_INSERT_HEAD(&allpmaps, pmap, pm_list);
for (size_t i = pmap_l1_index(VM_MIN_KERNEL_ADDRESS);
i < pmap_l1_index(VM_MAX_KERNEL_ADDRESS); i++)
if (pmap_mode == PMAP_MODE_SV39) {
/*
* Copy L1 entries from the kernel pmap. This must be done with
* the allpmaps lock held to avoid races with
* pmap_distribute_l1().
*/
mtx_lock(&allpmaps_lock);
LIST_INSERT_HEAD(&allpmaps, pmap, pm_list);
for (i = pmap_l1_index(VM_MIN_KERNEL_ADDRESS);
i < pmap_l1_index(VM_MAX_KERNEL_ADDRESS); i++)
pmap->pm_top[i] = kernel_pmap->pm_top[i];
for (i = pmap_l1_index(DMAP_MIN_ADDRESS);
i < pmap_l1_index(DMAP_MAX_ADDRESS); i++)
pmap->pm_top[i] = kernel_pmap->pm_top[i];
mtx_unlock(&allpmaps_lock);
} else {
i = pmap_l0_index(VM_MIN_KERNEL_ADDRESS);
pmap->pm_top[i] = kernel_pmap->pm_top[i];
for (size_t i = pmap_l1_index(DMAP_MIN_ADDRESS);
i < pmap_l1_index(DMAP_MAX_ADDRESS); i++)
pmap->pm_top[i] = kernel_pmap->pm_top[i];
mtx_unlock(&allpmaps_lock);
}
vm_radix_init(&pmap->pm_root);
@ -1480,9 +1492,11 @@ pmap_release(pmap_t pmap)
KASSERT(CPU_EMPTY(&pmap->pm_active),
("releasing active pmap %p", pmap));
mtx_lock(&allpmaps_lock);
LIST_REMOVE(pmap, pm_list);
mtx_unlock(&allpmaps_lock);
if (pmap_mode == PMAP_MODE_SV39) {
mtx_lock(&allpmaps_lock);
LIST_REMOVE(pmap, pm_list);
mtx_unlock(&allpmaps_lock);
}
m = PHYS_TO_VM_PAGE(DMAP_TO_PHYS((vm_offset_t)pmap->pm_top));
vm_page_unwire_noq(m);