[src/trunk]: src/sys/arch Introduce a new svs_page_add function, which can be...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/63318b649740
branches:  trunk
changeset: 358653:63318b649740
user:      maxv <maxv%NetBSD.org@localhost>
date:      Thu Jan 11 13:35:15 2018 +0000

description:
Introduce a new svs_page_add function, which can be used to map in the user
space a VA from the kernel space.

Use it to replace the PDIR_SLOT_PCPU slot: at boot time each CPU creates
its own slot which maps only its own pcpu_entry plus the common area (IDT+
LDT).

This way, the pcpu areas of the remote CPUs are not mapped in userland.

diffstat:

 sys/arch/amd64/amd64/machdep.c |  80 ++++++++++++++++++++++++++++++++++++++++-
 sys/arch/x86/x86/cpu.c         |  12 +++---
 2 files changed, 83 insertions(+), 9 deletions(-)

diffs (158 lines):

diff -r 5595231fff17 -r 63318b649740 sys/arch/amd64/amd64/machdep.c
--- a/sys/arch/amd64/amd64/machdep.c    Thu Jan 11 11:15:34 2018 +0000
+++ b/sys/arch/amd64/amd64/machdep.c    Thu Jan 11 13:35:15 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: machdep.c,v 1.288 2018/01/11 10:38:13 maxv Exp $       */
+/*     $NetBSD: machdep.c,v 1.289 2018/01/11 13:35:15 maxv Exp $       */
 
 /*
  * Copyright (c) 1996, 1997, 1998, 2000, 2006, 2007, 2008, 2011
@@ -110,7 +110,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.288 2018/01/11 10:38:13 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.289 2018/01/11 13:35:15 maxv Exp $");
 
 /* #define XENDEBUG_LOW  */
 
@@ -2264,9 +2264,76 @@
  * TODO: for now, only PMAP_SLOT_PTE is unmapped.
  */
 
+static void
+svs_page_add(struct cpu_info *ci, vaddr_t va)
+{
+       extern pd_entry_t * const normal_pdes[];
+       extern const vaddr_t ptp_masks[];
+       extern const int ptp_shifts[];
+       extern const long nbpd[];
+       pd_entry_t *srcpde, *dstpde;
+       size_t i, idx, pidx, mod;
+       struct vm_page *pg;
+       paddr_t pa;
+
+       KASSERT(va % PAGE_SIZE == 0);
+
+       dstpde = ci->ci_svs_updir;
+       mod = (size_t)-1;
+
+       for (i = PTP_LEVELS; i > 1; i--) {
+               idx = pl_i(va, i);
+               srcpde = normal_pdes[i - 2];
+
+               if (!pmap_valid_entry(srcpde[idx])) {
+                       panic("%s: page not mapped", __func__);
+               }
+               pidx = pl_i(va % mod, i);
+
+               if (!pmap_valid_entry(dstpde[pidx])) {
+                       pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_ZERO);
+                       if (pg == 0)
+                               panic("%s: failed to allocate PA for CPU %d\n",
+                                       __func__, cpu_index(ci));
+                       pa = VM_PAGE_TO_PHYS(pg);
+
+                       dstpde[pidx] = PG_V | PG_RW | pa;
+               }
+
+               pa = (paddr_t)(dstpde[pidx] & PG_FRAME);
+               dstpde = (pd_entry_t *)PMAP_DIRECT_MAP(pa);
+               mod = nbpd[i-1];
+       }
+
+       /* Do the last level manually */
+       idx = pl_i(va, 1);
+       srcpde = L1_BASE;
+       if (!pmap_valid_entry(srcpde[idx])) {
+               panic("%s: L1 page not mapped", __func__);
+       }
+       pidx = pl_i(va % mod, 1);
+       if (pmap_valid_entry(dstpde[pidx])) {
+               panic("%s: L1 page already mapped", __func__);
+       }
+       dstpde[pidx] = srcpde[idx];
+}
+
+static void
+svs_range_add(struct cpu_info *ci, vaddr_t va, size_t size)
+{
+       size_t i, n;
+
+       KASSERT(size % PAGE_SIZE == 0);
+       n = size / PAGE_SIZE;
+       for (i = 0; i < n; i++) {
+               svs_page_add(ci, va + i * PAGE_SIZE);
+       }
+}
+
 void
 cpu_svs_init(struct cpu_info *ci)
 {
+       const cpuid_t cid = cpu_index(ci);
        struct vm_page *pg;
 
        KASSERT(ci != NULL);
@@ -2291,6 +2358,11 @@
        ci->ci_svs_kpdirpa = pmap_pdirpa(pmap_kernel(), 0);
 
        mutex_init(&ci->ci_svs_mtx, MUTEX_DEFAULT, IPL_VM);
+
+       svs_page_add(ci, (vaddr_t)&pcpuarea->idt);
+       svs_page_add(ci, (vaddr_t)&pcpuarea->ldt);
+       svs_range_add(ci, (vaddr_t)&pcpuarea->ent[cid],
+           sizeof(struct pcpu_entry));
 }
 
 void
@@ -2364,7 +2436,9 @@
                 * This is where we decide what to unmap from the user page
                 * tables.
                 */
-               if (pmap_direct_pdpe <= i &&
+               if (i == PDIR_SLOT_PCPU) {
+                       /* keep the one created at boot time */
+               } else if (pmap_direct_pdpe <= i &&
                    i < pmap_direct_pdpe + pmap_direct_npdp) {
                        ci->ci_svs_updir[i] = 0;
                } else if (i == PDIR_SLOT_PTE) {
diff -r 5595231fff17 -r 63318b649740 sys/arch/x86/x86/cpu.c
--- a/sys/arch/x86/x86/cpu.c    Thu Jan 11 11:15:34 2018 +0000
+++ b/sys/arch/x86/x86/cpu.c    Thu Jan 11 13:35:15 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cpu.c,v 1.145 2018/01/11 09:18:16 msaitoh Exp $        */
+/*     $NetBSD: cpu.c,v 1.146 2018/01/11 13:35:15 maxv Exp $   */
 
 /*
  * Copyright (c) 2000-2012 NetBSD Foundation, Inc.
@@ -62,7 +62,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.145 2018/01/11 09:18:16 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.146 2018/01/11 13:35:15 maxv Exp $");
 
 #include "opt_ddb.h"
 #include "opt_mpbios.h"                /* for MPDEBUG */
@@ -380,10 +380,6 @@
        /* Must be before mi_cpu_attach(). */
        cpu_vm_init(ci);
 
-#ifdef SVS
-       cpu_svs_init(ci);
-#endif
-
        if (caa->cpu_role == CPU_ROLE_AP) {
                int error;
 
@@ -401,6 +397,10 @@
                KASSERT(ci->ci_data.cpu_idlelwp != NULL);
        }
 
+#ifdef SVS
+       cpu_svs_init(ci);
+#endif
+
        pmap_reference(pmap_kernel());
        ci->ci_pmap = pmap_kernel();
        ci->ci_tlbstate = TLBSTATE_STALE;