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[PATCH 5/9] use L4 page table directly on x86_64 instead of short-circui
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From: |
Luca Dariz |
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Subject: |
[PATCH 5/9] use L4 page table directly on x86_64 instead of short-circuiting to pdpbase |
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Date: |
Sun, 12 Feb 2023 18:28:14 +0100 |
This is a preparation to run the kernel on high addresses, where the
user vm region and the kernel vm region will use different L3 page
tables.
* i386/intel/pmap.c: on x86_64, retrieve the value of pdpbase from the
L4 table, and add the pmap_pdp() helper (useful also for PAE).
* i386/intel/pmap.h: remove pdpbase on x86_64.
---
i386/intel/pmap.c | 97 ++++++++++++++++++++++++++++++++++++-----------
i386/intel/pmap.h | 7 ++--
2 files changed, 78 insertions(+), 26 deletions(-)
diff --git a/i386/intel/pmap.c b/i386/intel/pmap.c
index 470be744..9e9f91db 100644
--- a/i386/intel/pmap.c
+++ b/i386/intel/pmap.c
@@ -430,14 +430,11 @@ pt_entry_t *kernel_page_dir;
static pmap_mapwindow_t mapwindows[PMAP_NMAPWINDOWS];
def_simple_lock_data(static, pmapwindows_lock)
+#ifdef PAE
static inline pt_entry_t *
-pmap_pde(const pmap_t pmap, vm_offset_t addr)
+pmap_ptp(const pmap_t pmap, vm_offset_t addr)
{
- pt_entry_t *page_dir;
- if (pmap == kernel_pmap)
- addr = kvtolin(addr);
-#if PAE
- pt_entry_t *pdp_table, pdp, pde;
+ pt_entry_t *pdp_table, pdp;
#ifdef __x86_64__
pdp = pmap->l4base[lin2l4num(addr)];
if ((pdp & INTEL_PTE_VALID) == 0)
@@ -446,6 +443,19 @@ pmap_pde(const pmap_t pmap, vm_offset_t addr)
#else /* __x86_64__ */
pdp_table = pmap->pdpbase;
#endif /* __x86_64__ */
+ return pdp_table;
+}
+#endif
+
+static inline pt_entry_t *
+pmap_pde(const pmap_t pmap, vm_offset_t addr)
+{
+ pt_entry_t *page_dir;
+ if (pmap == kernel_pmap)
+ addr = kvtolin(addr);
+#if PAE
+ pt_entry_t *pdp_table, pde;
+ pdp_table = pmap_ptp(pmap, addr);
pde = pdp_table[lin2pdpnum(addr)];
if ((pde & INTEL_PTE_VALID) == 0)
return PT_ENTRY_NULL;
@@ -585,6 +595,7 @@ vm_offset_t pmap_map_bd(
static void pmap_bootstrap_pae(void)
{
vm_offset_t addr;
+ pt_entry_t *pdp_kernel;
#ifdef __x86_64__
#ifdef MACH_HYP
@@ -595,13 +606,15 @@ static void pmap_bootstrap_pae(void)
memset(kernel_pmap->l4base, 0, INTEL_PGBYTES);
#endif /* x86_64 */
+ // TODO: allocate only the PDPTE for kernel virtual space
+ // this means all directmap and the stupid limit above it
init_alloc_aligned(PDPNUM * INTEL_PGBYTES, &addr);
kernel_page_dir = (pt_entry_t*)phystokv(addr);
- kernel_pmap->pdpbase = (pt_entry_t*)phystokv(pmap_grab_page());
- memset(kernel_pmap->pdpbase, 0, INTEL_PGBYTES);
+ pdp_kernel = (pt_entry_t*)phystokv(pmap_grab_page());
+ memset(pdp_kernel, 0, INTEL_PGBYTES);
for (int i = 0; i < PDPNUM; i++)
- WRITE_PTE(&kernel_pmap->pdpbase[i],
+ WRITE_PTE(&pdp_kernel[i],
pa_to_pte(_kvtophys((void *) kernel_page_dir
+ i * INTEL_PGBYTES))
| INTEL_PTE_VALID
@@ -611,10 +624,14 @@ static void pmap_bootstrap_pae(void)
);
#ifdef __x86_64__
- WRITE_PTE(&kernel_pmap->l4base[0],
pa_to_pte(_kvtophys(kernel_pmap->pdpbase)) | INTEL_PTE_VALID | INTEL_PTE_WRITE);
+ /* only fill the kernel pdpte during bootstrap */
+ WRITE_PTE(&kernel_pmap->l4base[lin2l4num(VM_MIN_KERNEL_ADDRESS)],
+ pa_to_pte(_kvtophys(pdp_kernel)) | INTEL_PTE_VALID |
INTEL_PTE_WRITE);
#ifdef MACH_PV_PAGETABLES
pmap_set_page_readonly_init(kernel_pmap->l4base);
-#endif
+#endif /* MACH_PV_PAGETABLES */
+#else /* x86_64 */
+ kernel_pmap->pdpbase = pdp_kernel;
#endif /* x86_64 */
}
#endif /* PAE */
@@ -1243,7 +1260,7 @@ pmap_page_table_page_dealloc(vm_offset_t pa)
*/
pmap_t pmap_create(vm_size_t size)
{
- pt_entry_t *page_dir[PDPNUM];
+ pt_entry_t *page_dir[PDPNUM], *pdp_kernel;
int i;
pmap_t p;
pmap_statistics_t stats;
@@ -1301,34 +1318,40 @@ pmap_t pmap_create(vm_size_t size)
#endif /* MACH_PV_PAGETABLES */
#if PAE
- p->pdpbase = (pt_entry_t *) kmem_cache_alloc(&pdpt_cache);
- if (p->pdpbase == NULL) {
+ pdp_kernel = (pt_entry_t *) kmem_cache_alloc(&pdpt_cache);
+ if (pdp_kernel == NULL) {
for (i = 0; i < PDPNUM; i++)
kmem_cache_free(&pd_cache, (vm_address_t) page_dir[i]);
kmem_cache_free(&pmap_cache, (vm_address_t) p);
return PMAP_NULL;
}
- memset(p->pdpbase, 0, INTEL_PGBYTES);
+ memset(pdp_kernel, 0, INTEL_PGBYTES);
{
for (i = 0; i < PDPNUM; i++)
- WRITE_PTE(&p->pdpbase[i],
+ WRITE_PTE(&pdp_kernel[i],
pa_to_pte(kvtophys((vm_offset_t) page_dir[i]))
| INTEL_PTE_VALID
#if (defined(__x86_64__) && !defined(MACH_HYP)) || defined(MACH_PV_PAGETABLES)
| INTEL_PTE_WRITE
#ifdef __x86_64__
| INTEL_PTE_USER
-#endif
+#endif /* __x86_64__ */
#endif
);
}
#ifdef __x86_64__
+ // TODO alloc only PDPTE for the user range VM_MIN_ADDRESS,
VM_MAX_ADDRESS
+ // and keep the same for kernel range, in l4 table we have different
entries
p->l4base = (pt_entry_t *) kmem_cache_alloc(&l4_cache);
if (p->l4base == NULL)
panic("pmap_create");
memset(p->l4base, 0, INTEL_PGBYTES);
- WRITE_PTE(&p->l4base[0], pa_to_pte(kvtophys((vm_offset_t) p->pdpbase))
| INTEL_PTE_VALID | INTEL_PTE_WRITE | INTEL_PTE_USER);
+ WRITE_PTE(&p->l4base[lin2l4num(VM_MIN_KERNEL_ADDRESS)],
+ pa_to_pte(kvtophys((vm_offset_t) pdp_kernel)) |
INTEL_PTE_VALID | INTEL_PTE_WRITE | INTEL_PTE_USER);
+#if lin2l4num(VM_MIN_KERNEL_ADDRESS) != lin2l4num(VM_MAX_ADDRESS)
+ // TODO kernel vm and user vm are not in the same l4 entry, so add the
user one
+#endif
#ifdef MACH_PV_PAGETABLES
// FIXME: use kmem_cache_alloc instead
if (kmem_alloc_wired(kernel_map,
@@ -1349,6 +1372,8 @@ pmap_t pmap_create(vm_size_t size)
memset(p->user_l4base, 0, INTEL_PGBYTES);
WRITE_PTE(&p->user_l4base[0], pa_to_pte(kvtophys((vm_offset_t)
p->user_pdpbase)) | INTEL_PTE_VALID | INTEL_PTE_WRITE);
#endif /* MACH_PV_PAGETABLES */
+#else /* _x86_64 */
+ p->pdpbase = pdp_kernel;
#endif /* _x86_64 */
#ifdef MACH_PV_PAGETABLES
#ifdef __x86_64__
@@ -1411,12 +1436,22 @@ void pmap_destroy(pmap_t p)
#if PAE
for (i = 0; i <= lin2pdpnum(LINEAR_MIN_KERNEL_ADDRESS); i++) {
- free_all = i < lin2pdpnum(LINEAR_MIN_KERNEL_ADDRESS);
- page_dir = (pt_entry_t *) ptetokv(p->pdpbase[i]);
+#ifdef __x86_64__
+#ifdef USER32
+ /* In this case we know we have one PDP for user space */
+ pt_entry_t *pdp = (pt_entry_t *)
ptetokv(p->l4base[lin2l4num(VM_MIN_ADDRESS)]);
#else
+#error "TODO do 64-bit userspace need more that 512G?"
+#endif /* USER32 */
+ page_dir = (pt_entry_t *) ptetokv(pdp[i]);
+#else /* __x86_64__ */
+ page_dir = (pt_entry_t *) ptetokv(p->pdpbase[i]);
+#endif /* __x86_64__ */
+ free_all = i < lin2pdpnum(LINEAR_MIN_KERNEL_ADDRESS);
+#else /* PAE */
free_all = FALSE;
page_dir = p->dirbase;
-#endif
+#endif /* PAE */
#ifdef __x86_64__
#warning FIXME 64bit need to free l3
@@ -1464,14 +1499,20 @@ void pmap_destroy(pmap_t p)
#endif /* __x86_64__ */
pmap_set_page_readwrite(p->pdpbase);
#endif /* MACH_PV_PAGETABLES */
+
#ifdef __x86_64__
+ kmem_cache_free(&pdpt_cache, (vm_offset_t) pmap_ptp(p, VM_MIN_ADDRESS));
+#if lin2l4num(VM_MIN_KERNEL_ADDRESS) != lin2l4num(VM_MAX_ADDRESS)
+ // TODO kernel vm and user vm are not in the same l4 entry
+#endif
kmem_cache_free(&l4_cache, (vm_offset_t) p->l4base);
#ifdef MACH_PV_PAGETABLES
kmem_free(kernel_map, (vm_offset_t)p->user_l4base, INTEL_PGBYTES);
kmem_free(kernel_map, (vm_offset_t)p->user_pdpbase, INTEL_PGBYTES);
#endif /* MACH_PV_PAGETABLES */
-#endif /* __x86_64__ */
+#else /* __x86_64__ */
kmem_cache_free(&pdpt_cache, (vm_offset_t) p->pdpbase);
+#endif /* __x86_64__ */
#endif /* PAE */
kmem_cache_free(&pmap_cache, (vm_offset_t) p);
}
@@ -2404,8 +2445,18 @@ void pmap_collect(pmap_t p)
#if PAE
for (i = 0; i <= lin2pdpnum(LINEAR_MIN_KERNEL_ADDRESS); i++) {
- free_all = i < lin2pdpnum(LINEAR_MIN_KERNEL_ADDRESS);
+#ifdef __x86_64__
+#ifdef USER32
+ /* In this case we know we have one PDP for user space */
+ pdp = (pt_entry_t *) ptetokv(p->l4base[lin2l4num(VM_MIN_ADDRESS)]);
+#else
+#error "TODO do 64-bit userspace need more that 512G?"
+#endif /* USER32 */
+ page_dir = (pt_entry_t *) ptetokv(pdp[i]);
+#else /* __x86_64__ */
page_dir = (pt_entry_t *) ptetokv(p->pdpbase[i]);
+#endif /* __x86_64__ */
+ free_all = i < lin2pdpnum(LINEAR_MIN_KERNEL_ADDRESS);
#else
i = 0;
free_all = FALSE;
diff --git a/i386/intel/pmap.h b/i386/intel/pmap.h
index 92247faa..1c6a0d30 100644
--- a/i386/intel/pmap.h
+++ b/i386/intel/pmap.h
@@ -182,16 +182,17 @@ typedef volatile long cpu_set; /* set of CPUs
- must be <= 32 */
struct pmap {
#if ! PAE
pt_entry_t *dirbase; /* page directory table */
-#else
- pt_entry_t *pdpbase; /* page directory pointer table */
-#endif /* ! PAE */
+#else /* PAE */
#ifdef __x86_64__
pt_entry_t *l4base; /* l4 table */
#ifdef MACH_HYP
pt_entry_t *user_l4base; /* Userland l4 table */
pt_entry_t *user_pdpbase; /* Userland l4 table */
#endif /* MACH_HYP */
+#else /* x86_64 */
+ pt_entry_t *pdpbase; /* page directory pointer table */
#endif /* x86_64 */
+#endif /* PAE */
int ref_count; /* reference count */
decl_simple_lock_data(,lock)
/* lock on map */
--
2.30.2
- [PATCH 0/9 gnumach] move kernel vm map to high addresses on x86_64, Luca Dariz, 2023/02/12
- [PATCH 6/9] add more explicit names for user space virtual space limits, Luca Dariz, 2023/02/12
- [PATCH 5/9] use L4 page table directly on x86_64 instead of short-circuiting to pdpbase,
Luca Dariz <=
- [PATCH 1/9] prepare pmap helpers for full 64 bit memory map, Luca Dariz, 2023/02/12
- [PATCH 2/9] fix x86_64 asm for higher kernel addresses, Luca Dariz, 2023/02/12
- [PATCH 3/9] factor out xen-specific bootstrap, Luca Dariz, 2023/02/12
- [PATCH 4/9] factor out PAE-specific bootstrap, Luca Dariz, 2023/02/12
- [PATCH 7/9] extend data types to hold a 64-bit address, Luca Dariz, 2023/02/12