[Lguest] [PATCH] lguest: PAE support
Matias Zabaljauregui
zabaljauregui at gmail.com
Sat Jun 6 02:09:02 EST 2009
Hi, this version requires that host and guest have the same PAE status.
NX cap is not offered to the guest, yet.
Thanks,
Matias
Lguest PAE support
Signed-off-by: Matias Zabaljauregui <zabaljauregui at gmail.com>
---
Documentation/lguest/lguest.txt | 1 -
arch/x86/include/asm/lguest.h | 7 +-
arch/x86/include/asm/lguest_hcall.h | 3 +-
arch/x86/lguest/Kconfig | 1 -
arch/x86/lguest/boot.c | 79 +++++++-
drivers/lguest/Kconfig | 2 +-
drivers/lguest/hypercalls.c | 10 +
drivers/lguest/lg.h | 5 +
drivers/lguest/page_tables.c | 356 +++++++++++++++++++++++++++++++----
9 files changed, 410 insertions(+), 54 deletions(-)
diff --git a/Documentation/lguest/lguest.txt b/Documentation/lguest/lguest.txt
index 28c7473..efb3a6a 100644
--- a/Documentation/lguest/lguest.txt
+++ b/Documentation/lguest/lguest.txt
@@ -37,7 +37,6 @@ Running Lguest:
"Paravirtualized guest support" = Y
"Lguest guest support" = Y
"High Memory Support" = off/4GB
- "PAE (Physical Address Extension) Support" = N
"Alignment value to which kernel should be aligned" = 0x100000
(CONFIG_PARAVIRT=y, CONFIG_LGUEST_GUEST=y, CONFIG_HIGHMEM64G=n and
CONFIG_PHYSICAL_ALIGN=0x100000)
diff --git a/arch/x86/include/asm/lguest.h b/arch/x86/include/asm/lguest.h
index 1caf576..313389c 100644
--- a/arch/x86/include/asm/lguest.h
+++ b/arch/x86/include/asm/lguest.h
@@ -17,8 +17,13 @@
/* Pages for switcher itself, then two pages per cpu */
#define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * nr_cpu_ids)
-/* We map at -4M for ease of mapping into the guest (one PTE page). */
+/* We map at -4M (-2M when PAE is activated) for ease of mapping
+ * into the guest (one PTE page). */
+#ifdef CONFIG_X86_PAE
+#define SWITCHER_ADDR 0xFFE00000
+#else
#define SWITCHER_ADDR 0xFFC00000
+#endif
/* Found in switcher.S */
extern unsigned long default_idt_entries[];
diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h
index 553810f..7ba1d81 100644
--- a/arch/x86/include/asm/lguest_hcall.h
+++ b/arch/x86/include/asm/lguest_hcall.h
@@ -12,6 +12,7 @@
#define LHCALL_TS 8
#define LHCALL_SET_CLOCKEVENT 9
#define LHCALL_HALT 10
+#define LHCALL_SET_PMD 13
#define LHCALL_SET_PTE 14
#define LHCALL_SET_PGD 15
#define LHCALL_LOAD_TLS 16
@@ -32,7 +33,7 @@
* operations? There are two ways: the direct way is to make a "hypercall",
* to make requests of the Host Itself.
*
- * We use the KVM hypercall mechanism. Eighteen hypercalls are
+ * We use the KVM hypercall mechanism. Sixteen hypercalls are
* available: the hypercall number is put in the %eax register, and the
* arguments (when required) are placed in %ebx, %ecx, %edx and %esi.
* If a return value makes sense, it's returned in %eax.
diff --git a/arch/x86/lguest/Kconfig b/arch/x86/lguest/Kconfig
index 8dab8f7..3871804 100644
--- a/arch/x86/lguest/Kconfig
+++ b/arch/x86/lguest/Kconfig
@@ -2,7 +2,6 @@ config LGUEST_GUEST
bool "Lguest guest support"
select PARAVIRT
depends on X86_32
- depends on !X86_PAE
select VIRTIO
select VIRTIO_RING
select VIRTIO_CONSOLE
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 3b9339e..f2c8003 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -166,6 +166,7 @@ static void lazy_hcall3(unsigned long call,
async_hcall(call, arg1, arg2, arg3, 0);
}
+#ifdef CONFIG_X86_PAE
static void lazy_hcall4(unsigned long call,
unsigned long arg1,
unsigned long arg2,
@@ -177,6 +178,7 @@ static void lazy_hcall4(unsigned long call,
else
async_hcall(call, arg1, arg2, arg3, arg4);
}
+#endif
/* When lazy mode is turned off reset the per-cpu lazy mode variable and then
* issue the do-nothing hypercall to flush any stored calls. */
@@ -375,8 +377,8 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
case 1: /* Basic feature request. */
/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
*cx &= 0x00002201;
- /* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU. */
- *dx &= 0x07808111;
+ /* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU, PAE. */
+ *dx &= 0x07808151;
/* The Host can do a nice optimization if it knows that the
* kernel mappings (addresses above 0xC0000000 or whatever
* PAGE_OFFSET is set to) haven't changed. But Linux calls
@@ -395,6 +397,11 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
if (*ax > 0x80000008)
*ax = 0x80000008;
break;
+ case 0x80000001:
+ /* Here we should fix nx cap depending on host. */
+ /* For this version of PAE, we just clear NX bit. */
+ *dx &= ~(1 << 20);
+ break;
}
}
@@ -528,25 +535,52 @@ static void lguest_write_cr4(unsigned long val)
static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
+#ifdef CONFIG_X86_PAE
+ lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr,
+ ptep->pte_low, ptep->pte_high);
+#else
lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);
+#endif
}
static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pteval)
{
- *ptep = pteval;
+ native_set_pte(ptep, pteval);
lguest_pte_update(mm, addr, ptep);
}
-/* The Guest calls this to set a top-level entry. Again, we set the entry then
- * tell the Host which top-level page we changed, and the index of the entry we
- * changed. */
+/* The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd
+ * to set a middle-level entry when PAE is activated.
+ * Again, we set the entry then tell the Host which page we changed,
+ * and the index of the entry we changed. */
+#ifdef CONFIG_X86_PAE
+static void lguest_set_pud(pud_t *pudp, pud_t pudval)
+{
+ native_set_pud(pudp, pudval);
+
+ /* 32 bytes aligned pdpt address and the index. */
+ lazy_hcall2(LHCALL_SET_PGD, __pa(pudp) & 0xFFFFFFE0,
+ (__pa(pudp) & 0x1F) / sizeof(pud_t));
+}
+
static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
{
- *pmdp = pmdval;
+ native_set_pmd(pmdp, pmdval);
+ lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,
+ (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
+}
+#else
+
+/* The Guest calls lguest_set_pmd to set a top-level entry when PAE is not
+ * activated. */
+static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
+{
+ native_set_pmd(pmdp, pmdval);
lazy_hcall2(LHCALL_SET_PGD, __pa(pmdp) & PAGE_MASK,
- (__pa(pmdp) & (PAGE_SIZE - 1)) / 4);
+ (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));
}
+#endif
/* There are a couple of legacy places where the kernel sets a PTE, but we
* don't know the top level any more. This is useless for us, since we don't
@@ -559,11 +593,31 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
* which brings boot back to 0.25 seconds. */
static void lguest_set_pte(pte_t *ptep, pte_t pteval)
{
- *ptep = pteval;
+ native_set_pte(ptep, pteval);
+ if (cr3_changed)
+ lazy_hcall1(LHCALL_FLUSH_TLB, 1);
+}
+
+#ifdef CONFIG_X86_PAE
+static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+ native_set_pte_atomic(ptep, pte);
if (cr3_changed)
lazy_hcall1(LHCALL_FLUSH_TLB, 1);
}
+void lguest_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+ native_pte_clear(mm, addr, ptep);
+ lguest_pte_update(mm, addr, ptep);
+}
+
+void lguest_pmd_clear(pmd_t *pmdp)
+{
+ lguest_set_pmd(pmdp, __pmd(0));
+}
+#endif
+
/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
* native page table operations. On native hardware you can set a new page
* table entry whenever you want, but if you want to remove one you have to do
@@ -1033,6 +1087,7 @@ __init void lguest_init(void)
pv_info.name = "lguest";
pv_info.paravirt_enabled = 1;
pv_info.kernel_rpl = 1;
+ pv_info.shared_kernel_pmd = 1;
/* We set up all the lguest overrides for sensitive operations. These
* are detailed with the operations themselves. */
@@ -1078,6 +1133,12 @@ __init void lguest_init(void)
pv_mmu_ops.set_pte = lguest_set_pte;
pv_mmu_ops.set_pte_at = lguest_set_pte_at;
pv_mmu_ops.set_pmd = lguest_set_pmd;
+#ifdef CONFIG_X86_PAE
+ pv_mmu_ops.set_pte_atomic = lguest_set_pte_atomic;
+ pv_mmu_ops.pte_clear = lguest_pte_clear;
+ pv_mmu_ops.pmd_clear = lguest_pmd_clear;
+ pv_mmu_ops.set_pud = lguest_set_pud;
+#endif
pv_mmu_ops.read_cr2 = lguest_read_cr2;
pv_mmu_ops.read_cr3 = lguest_read_cr3;
pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;
diff --git a/drivers/lguest/Kconfig b/drivers/lguest/Kconfig
index a3d3cba..8f63845 100644
--- a/drivers/lguest/Kconfig
+++ b/drivers/lguest/Kconfig
@@ -1,6 +1,6 @@
config LGUEST
tristate "Linux hypervisor example code"
- depends on X86_32 && EXPERIMENTAL && !X86_PAE && FUTEX
+ depends on X86_32 && EXPERIMENTAL && FUTEX
select HVC_DRIVER
---help---
This is a very simple module which allows you to run
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
index 1cc3377..5415da1 100644
--- a/drivers/lguest/hypercalls.c
+++ b/drivers/lguest/hypercalls.c
@@ -73,11 +73,21 @@ static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);
break;
case LHCALL_SET_PTE:
+#ifdef CONFIG_X86_PAE
+ guest_set_pte(cpu, args->arg1, args->arg2,
+ __pte(args->arg3 | (u64)args->arg4 << 32));
+#else
guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3));
+#endif
break;
case LHCALL_SET_PGD:
guest_set_pgd(cpu->lg, args->arg1, args->arg2);
break;
+#ifdef CONFIG_X86_PAE
+ case LHCALL_SET_PMD:
+ guest_set_pmd(cpu->lg, args->arg1, args->arg2);
+ break;
+#endif
case LHCALL_SET_CLOCKEVENT:
guest_set_clockevent(cpu, args->arg1);
break;
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
index 5e7a27d..ce56ef8 100644
--- a/drivers/lguest/lg.h
+++ b/drivers/lguest/lg.h
@@ -137,6 +137,8 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
* in the kernel. */
#define pgd_flags(x) (pgd_val(x) & ~PAGE_MASK)
#define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT)
+#define pmd_flags(x) (pmd_val(x) & ~PAGE_MASK)
+#define pmd_pfn(x) (pmd_val(x) >> PAGE_SHIFT)
/* interrupts_and_traps.c: */
void maybe_do_interrupt(struct lg_cpu *cpu);
@@ -169,6 +171,9 @@ int init_guest_pagetable(struct lguest *lg);
void free_guest_pagetable(struct lguest *lg);
void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 i);
+#ifdef CONFIG_X86_PAE
+void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
+#endif
void guest_pagetable_clear_all(struct lg_cpu *cpu);
void guest_pagetable_flush_user(struct lg_cpu *cpu);
void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c
index 8a3c3a5..a03b74b 100644
--- a/drivers/lguest/page_tables.c
+++ b/drivers/lguest/page_tables.c
@@ -53,6 +53,17 @@
* page. */
#define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1)
+/* For PAE we need the PMD index as well. We use the last 2MB, so we
+ * will need the last pmd entry of the last pmd page. */
+#ifdef CONFIG_X86_PAE
+#define SWITCHER_PMD_INDEX (PTRS_PER_PMD - 1)
+#define RESERVE_MEM 2U
+#define CHECK_GPGD_MASK _PAGE_PRESENT
+#else
+#define RESERVE_MEM 4U
+#define CHECK_GPGD_MASK _PAGE_TABLE
+#endif
+
/* We actually need a separate PTE page for each CPU. Remember that after the
* Switcher code itself comes two pages for each CPU, and we don't want this
* CPU's guest to see the pages of any other CPU. */
@@ -73,23 +84,58 @@ static pgd_t *spgd_addr(struct lg_cpu *cpu, u32 i, unsigned long vaddr)
{
unsigned int index = pgd_index(vaddr);
+#ifndef CONFIG_X86_PAE
/* We kill any Guest trying to touch the Switcher addresses. */
if (index >= SWITCHER_PGD_INDEX) {
kill_guest(cpu, "attempt to access switcher pages");
index = 0;
}
+#endif
/* Return a pointer index'th pgd entry for the i'th page table. */
return &cpu->lg->pgdirs[i].pgdir[index];
}
+#ifdef CONFIG_X86_PAE
+/* This routine then takes the PGD entry given above, which contains the
+ * address of the PMD page. It then returns a pointer to the PMD entry for the
+ * given address. */
+static pmd_t *spmd_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
+{
+ unsigned int index = pmd_index(vaddr);
+ pmd_t *page;
+
+ /* We kill any Guest trying to touch the Switcher addresses. */
+ if (pgd_index(vaddr) == SWITCHER_PGD_INDEX &&
+ index >= SWITCHER_PMD_INDEX) {
+ kill_guest(cpu, "attempt to access switcher pages");
+ index = 0;
+ }
+
+ /* You should never call this if the PGD entry wasn't valid */
+ BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
+ page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
+
+ return &page[index];
+}
+#endif
+
/* This routine then takes the page directory entry returned above, which
* contains the address of the page table entry (PTE) page. It then returns a
* pointer to the PTE entry for the given address. */
-static pte_t *spte_addr(pgd_t spgd, unsigned long vaddr)
+static pte_t *spte_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr)
{
+#ifdef CONFIG_X86_PAE
+ pmd_t *pmd = spmd_addr(cpu, spgd, vaddr);
+ pte_t *page = __va(pmd_pfn(*pmd) << PAGE_SHIFT);
+
+ /* You should never call this if the PMD entry wasn't valid */
+ BUG_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT));
+#else
pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
/* You should never call this if the PGD entry wasn't valid */
BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
+#endif
+
return &page[pte_index(vaddr)];
}
@@ -101,10 +147,31 @@ static unsigned long gpgd_addr(struct lg_cpu *cpu, unsigned long vaddr)
return cpu->lg->pgdirs[cpu->cpu_pgd].gpgdir + index * sizeof(pgd_t);
}
-static unsigned long gpte_addr(pgd_t gpgd, unsigned long vaddr)
+#ifdef CONFIG_X86_PAE
+static unsigned long gpmd_addr(pgd_t gpgd, unsigned long vaddr)
{
unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
+ return gpage + pmd_index(vaddr) * sizeof(pmd_t);
+}
+#endif
+
+static unsigned long gpte_addr(struct lg_cpu *cpu,
+ pgd_t gpgd, unsigned long vaddr)
+{
+#ifdef CONFIG_X86_PAE
+ pmd_t gpmd;
+#endif
+ unsigned long gpage;
+
+ BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
+#ifdef CONFIG_X86_PAE
+ gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
+ gpage = pmd_pfn(gpmd) << PAGE_SHIFT;
+ BUG_ON(!(pmd_flags(gpmd) & _PAGE_PRESENT));
+#else
+ gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
+#endif
return gpage + pte_index(vaddr) * sizeof(pte_t);
}
/*:*/
@@ -184,11 +251,20 @@ static void check_gpte(struct lg_cpu *cpu, pte_t gpte)
static void check_gpgd(struct lg_cpu *cpu, pgd_t gpgd)
{
- if ((pgd_flags(gpgd) & ~_PAGE_TABLE) ||
+ if ((pgd_flags(gpgd) & ~CHECK_GPGD_MASK) ||
(pgd_pfn(gpgd) >= cpu->lg->pfn_limit))
kill_guest(cpu, "bad page directory entry");
}
+#ifdef CONFIG_X86_PAE
+static void check_gpmd(struct lg_cpu *cpu, pmd_t gpmd)
+{
+ if ((pmd_flags(gpmd) & ~_PAGE_TABLE) ||
+ (pmd_pfn(gpmd) >= cpu->lg->pfn_limit))
+ kill_guest(cpu, "bad page middle directory entry");
+}
+#endif
+
/*H:330
* (i) Looking up a page table entry when the Guest faults.
*
@@ -207,6 +283,11 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
pte_t gpte;
pte_t *spte;
+#ifdef CONFIG_X86_PAE
+ pmd_t *spmd;
+ pmd_t gpmd;
+#endif
+
/* First step: get the top-level Guest page table entry. */
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
/* Toplevel not present? We can't map it in. */
@@ -228,12 +309,40 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
check_gpgd(cpu, gpgd);
/* And we copy the flags to the shadow PGD entry. The page
* number in the shadow PGD is the page we just allocated. */
- *spgd = __pgd(__pa(ptepage) | pgd_flags(gpgd));
+ set_pgd(spgd, __pgd(__pa(ptepage) | pgd_flags(gpgd)));
}
+#ifdef CONFIG_X86_PAE
+ gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
+ /* middle level not present? We can't map it in. */
+ if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
+ return false;
+
+ /* Now look at the matching shadow entry. */
+ spmd = spmd_addr(cpu, *spgd, vaddr);
+
+ if (!(pmd_flags(*spmd) & _PAGE_PRESENT)) {
+ /* No shadow entry: allocate a new shadow PTE page. */
+ unsigned long ptepage = get_zeroed_page(GFP_KERNEL);
+
+ /* This is not really the Guest's fault, but killing it is
+ * simple for this corner case. */
+ if (!ptepage) {
+ kill_guest(cpu, "out of memory allocating pte page");
+ return false;
+ }
+
+ /* We check that the Guest pmd is OK. */
+ check_gpmd(cpu, gpmd);
+
+ /* And we copy the flags to the shadow PMD entry. The page
+ * number in the shadow PMD is the page we just allocated. */
+ native_set_pmd(spmd, __pmd(__pa(ptepage) | pmd_flags(gpmd)));
+ }
+#endif
/* OK, now we look at the lower level in the Guest page table: keep its
* address, because we might update it later. */
- gpte_ptr = gpte_addr(gpgd, vaddr);
+ gpte_ptr = gpte_addr(cpu, gpgd, vaddr);
gpte = lgread(cpu, gpte_ptr, pte_t);
/* If this page isn't in the Guest page tables, we can't page it in. */
@@ -259,7 +368,7 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode)
gpte = pte_mkdirty(gpte);
/* Get the pointer to the shadow PTE entry we're going to set. */
- spte = spte_addr(*spgd, vaddr);
+ spte = spte_addr(cpu, *spgd, vaddr);
/* If there was a valid shadow PTE entry here before, we release it.
* This can happen with a write to a previously read-only entry. */
release_pte(*spte);
@@ -301,14 +410,23 @@ static bool page_writable(struct lg_cpu *cpu, unsigned long vaddr)
pgd_t *spgd;
unsigned long flags;
+#ifdef CONFIG_X86_PAE
+ pmd_t *spmd;
+#endif
/* Look at the current top level entry: is it present? */
spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr);
if (!(pgd_flags(*spgd) & _PAGE_PRESENT))
return false;
+#ifdef CONFIG_X86_PAE
+ spmd = spmd_addr(cpu, *spgd, vaddr);
+ if (!(pmd_flags(*spmd) & _PAGE_PRESENT))
+ return false;
+#endif
+
/* Check the flags on the pte entry itself: it must be present and
* writable. */
- flags = pte_flags(*(spte_addr(*spgd, vaddr)));
+ flags = pte_flags(*(spte_addr(cpu, *spgd, vaddr)));
return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW);
}
@@ -322,6 +440,41 @@ void pin_page(struct lg_cpu *cpu, unsigned long vaddr)
kill_guest(cpu, "bad stack page %#lx", vaddr);
}
+#ifdef CONFIG_X86_PAE
+static void release_pmd(pmd_t *spmd)
+{
+ /* If the entry's not present, there's nothing to release. */
+ if (pmd_flags(*spmd) & _PAGE_PRESENT) {
+ unsigned int i;
+ pte_t *ptepage = __va(pmd_pfn(*spmd) << PAGE_SHIFT);
+ /* For each entry in the page, we might need to release it. */
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ release_pte(ptepage[i]);
+ /* Now we can free the page of PTEs */
+ free_page((long)ptepage);
+ /* And zero out the PMD entry so we never release it twice. */
+ native_set_pmd(spmd, __pmd(0));
+ }
+}
+
+static void release_pgd(pgd_t *spgd)
+{
+ /* If the entry's not present, there's nothing to release. */
+ if (pgd_flags(*spgd) & _PAGE_PRESENT) {
+ unsigned int i;
+ pmd_t *pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
+
+ for (i = 0; i < PTRS_PER_PMD; i++)
+ release_pmd(&pmdpage[i]);
+
+ /* Now we can free the page of PMDs */
+ free_page((long)pmdpage);
+ /* And zero out the PGD entry so we never release it twice. */
+ set_pgd(spgd, __pgd(0));
+ }
+}
+
+#else /* !CONFIG_X86_PAE */
/*H:450 If we chase down the release_pgd() code, it looks like this: */
static void release_pgd(pgd_t *spgd)
{
@@ -341,7 +494,7 @@ static void release_pgd(pgd_t *spgd)
*spgd = __pgd(0);
}
}
-
+#endif
/*H:445 We saw flush_user_mappings() twice: once from the flush_user_mappings()
* hypercall and once in new_pgdir() when we re-used a top-level pgdir page.
* It simply releases every PTE page from 0 up to the Guest's kernel address. */
@@ -370,6 +523,9 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
pgd_t gpgd;
pte_t gpte;
+#ifdef CONFIG_X86_PAE
+ pmd_t gpmd;
+#endif
/* First step: get the top-level Guest page table entry. */
gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t);
/* Toplevel not present? We can't map it in. */
@@ -378,7 +534,13 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr)
return -1UL;
}
- gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t);
+ gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);
+#ifdef CONFIG_X86_PAE
+ gpmd = lgread(cpu, gpmd_addr(gpgd, vaddr), pmd_t);
+ if (!(pmd_flags(gpmd) & _PAGE_PRESENT))
+ kill_guest(cpu, "Bad address %#lx", vaddr);
+#endif
+ gpte = lgread(cpu, gpte_addr(cpu, gpgd, vaddr), pte_t);
if (!(pte_flags(gpte) & _PAGE_PRESENT))
kill_guest(cpu, "Bad address %#lx", vaddr);
@@ -405,6 +567,9 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
int *blank_pgdir)
{
unsigned int next;
+#ifdef CONFIG_X86_PAE
+ pmd_t *pmd_table;
+#endif
/* We pick one entry at random to throw out. Choosing the Least
* Recently Used might be better, but this is easy. */
@@ -416,10 +581,27 @@ static unsigned int new_pgdir(struct lg_cpu *cpu,
/* If the allocation fails, just keep using the one we have */
if (!cpu->lg->pgdirs[next].pgdir)
next = cpu->cpu_pgd;
- else
- /* This is a blank page, so there are no kernel
- * mappings: caller must map the stack! */
+ else {
+#ifdef CONFIG_X86_PAE
+ /* In PAE mode, allocate a pmd page and populate the
+ * last pgd entry. */
+ pmd_table = (pmd_t *)get_zeroed_page(GFP_KERNEL);
+ if (!pmd_table) {
+ free_page((long)cpu->lg->pgdirs[next].pgdir);
+ set_pgd(cpu->lg->pgdirs[next].pgdir, __pgd(0));
+ next = cpu->cpu_pgd;
+ } else {
+ set_pgd(cpu->lg->pgdirs[next].pgdir +
+ SWITCHER_PGD_INDEX,
+ __pgd(__pa(pmd_table) | _PAGE_PRESENT));
+ /* This is a blank page, so there are no kernel
+ * mappings: caller must map the stack! */
+ *blank_pgdir = 1;
+ }
+#else
*blank_pgdir = 1;
+#endif
+ }
}
/* Record which Guest toplevel this shadows. */
cpu->lg->pgdirs[next].gpgdir = gpgdir;
@@ -460,10 +642,25 @@ static void release_all_pagetables(struct lguest *lg)
/* Every shadow pagetable this Guest has */
for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
- if (lg->pgdirs[i].pgdir)
+ if (lg->pgdirs[i].pgdir) {
+#ifdef CONFIG_X86_PAE
+ pgd_t *spgd;
+ pmd_t *pmdpage;
+ unsigned int k;
+
+ /* Get the last pmd page. */
+ spgd = lg->pgdirs[i].pgdir + SWITCHER_PGD_INDEX;
+ pmdpage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
+
+ /* And release the pmd entries of that pmd page,
+ * except for the switcher pmd. */
+ for (k = 0; k < SWITCHER_PMD_INDEX; k++)
+ release_pmd(&pmdpage[k]);
+#endif
/* Every PGD entry except the Switcher at the top */
for (j = 0; j < SWITCHER_PGD_INDEX; j++)
release_pgd(lg->pgdirs[i].pgdir + j);
+ }
}
/* We also throw away everything when a Guest tells us it's changed a kernel
@@ -504,24 +701,37 @@ static void do_set_pte(struct lg_cpu *cpu, int idx,
{
/* Look up the matching shadow page directory entry. */
pgd_t *spgd = spgd_addr(cpu, idx, vaddr);
+#ifdef CONFIG_X86_PAE
+ pmd_t *spmd;
+#endif
/* If the top level isn't present, there's no entry to update. */
if (pgd_flags(*spgd) & _PAGE_PRESENT) {
- /* Otherwise, we start by releasing the existing entry. */
- pte_t *spte = spte_addr(*spgd, vaddr);
- release_pte(*spte);
-
- /* If they're setting this entry as dirty or accessed, we might
- * as well put that entry they've given us in now. This shaves
- * 10% off a copy-on-write micro-benchmark. */
- if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
- check_gpte(cpu, gpte);
- *spte = gpte_to_spte(cpu, gpte,
- pte_flags(gpte) & _PAGE_DIRTY);
- } else
- /* Otherwise kill it and we can demand_page() it in
- * later. */
- *spte = __pte(0);
+#ifdef CONFIG_X86_PAE
+ spmd = spmd_addr(cpu, *spgd, vaddr);
+ if (pmd_flags(*spmd) & _PAGE_PRESENT) {
+#endif
+ /* Otherwise, we start by releasing
+ * the existing entry. */
+ pte_t *spte = spte_addr(cpu, *spgd, vaddr);
+ release_pte(*spte);
+
+ /* If they're setting this entry as dirty or accessed,
+ * we might as well put that entry they've given us
+ * in now. This shaves 10% off a
+ * copy-on-write micro-benchmark. */
+ if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
+ check_gpte(cpu, gpte);
+ native_set_pte(spte,
+ gpte_to_spte(cpu, gpte,
+ pte_flags(gpte) & _PAGE_DIRTY));
+ } else
+ /* Otherwise kill it and we can demand_page()
+ * it in later. */
+ native_set_pte(spte, __pte(0));
+#ifdef CONFIG_X86_PAE
+ }
+#endif
}
}
@@ -572,8 +782,6 @@ void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
{
int pgdir;
- /* The kernel seems to try to initialize this early on: we ignore its
- * attempts to map over the Switcher. */
if (idx >= SWITCHER_PGD_INDEX)
return;
@@ -583,6 +791,12 @@ void guest_set_pgd(struct lguest *lg, unsigned long gpgdir, u32 idx)
/* ... throw it away. */
release_pgd(lg->pgdirs[pgdir].pgdir + idx);
}
+#ifdef CONFIG_X86_PAE
+void guest_set_pmd(struct lguest *lg, unsigned long pmdp, u32 idx)
+{
+ guest_pagetable_clear_all(&lg->cpus[0]);
+}
+#endif
/* Once we know how much memory we have we can construct simple identity
* (which set virtual == physical) and linear mappings
@@ -596,8 +810,16 @@ static unsigned long setup_pagetables(struct lguest *lg,
{
pgd_t __user *pgdir;
pte_t __user *linear;
- unsigned int mapped_pages, i, linear_pages, phys_linear;
unsigned long mem_base = (unsigned long)lg->mem_base;
+ unsigned int mapped_pages, i, linear_pages;
+#ifdef CONFIG_X86_PAE
+ pmd_t __user *pmds;
+ unsigned int j;
+ pgd_t pgd;
+ pmd_t pmd;
+#else
+ unsigned int phys_linear;
+#endif
/* We have mapped_pages frames to map, so we need
* linear_pages page tables to map them. */
@@ -610,6 +832,9 @@ static unsigned long setup_pagetables(struct lguest *lg,
/* Now we use the next linear_pages pages as pte pages */
linear = (void *)pgdir - linear_pages * PAGE_SIZE;
+#ifdef CONFIG_X86_PAE
+ pmds = (void *)linear - PAGE_SIZE;
+#endif
/* Linear mapping is easy: put every page's address into the
* mapping in order. */
for (i = 0; i < mapped_pages; i++) {
@@ -621,6 +846,22 @@ static unsigned long setup_pagetables(struct lguest *lg,
/* The top level points to the linear page table pages above.
* We setup the identity and linear mappings here. */
+#ifdef CONFIG_X86_PAE
+ for (i = 0, j; i < mapped_pages && j < PTRS_PER_PMD;
+ i += PTRS_PER_PTE, j++) {
+ native_set_pmd(&pmd, __pmd(((unsigned long)(linear + i)
+ - mem_base) | _PAGE_PRESENT | _PAGE_RW | _PAGE_USER));
+
+ if (copy_to_user(&pmds[j], &pmd, sizeof(pmd)) != 0)
+ return -EFAULT;
+ }
+
+ set_pgd(&pgd, __pgd(((u32)pmds - mem_base) | _PAGE_PRESENT));
+ if (copy_to_user(&pgdir[0], &pgd, sizeof(pgd)) != 0)
+ return -EFAULT;
+ if (copy_to_user(&pgdir[3], &pgd, sizeof(pgd)) != 0)
+ return -EFAULT;
+#else
phys_linear = (unsigned long)linear - mem_base;
for (i = 0; i < mapped_pages; i += PTRS_PER_PTE) {
pgd_t pgd;
@@ -633,6 +874,7 @@ static unsigned long setup_pagetables(struct lguest *lg,
&pgd, sizeof(pgd)))
return -EFAULT;
}
+#endif
/* We return the top level (guest-physical) address: remember where
* this is. */
@@ -648,7 +890,10 @@ int init_guest_pagetable(struct lguest *lg)
u64 mem;
u32 initrd_size;
struct boot_params __user *boot = (struct boot_params *)lg->mem_base;
-
+#ifdef CONFIG_X86_PAE
+ pgd_t *pgd;
+ pmd_t *pmd_table;
+#endif
/* Get the Guest memory size and the ramdisk size from the boot header
* located at lg->mem_base (Guest address 0). */
if (copy_from_user(&mem, &boot->e820_map[0].size, sizeof(mem))
@@ -663,6 +908,15 @@ int init_guest_pagetable(struct lguest *lg)
lg->pgdirs[0].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL);
if (!lg->pgdirs[0].pgdir)
return -ENOMEM;
+#ifdef CONFIG_X86_PAE
+ pgd = lg->pgdirs[0].pgdir;
+ pmd_table = (pmd_t *) get_zeroed_page(GFP_KERNEL);
+ if (!pmd_table)
+ return -ENOMEM;
+
+ set_pgd(pgd + SWITCHER_PGD_INDEX,
+ __pgd(__pa(pmd_table) | _PAGE_PRESENT));
+#endif
lg->cpus[0].cpu_pgd = 0;
return 0;
}
@@ -672,17 +926,24 @@ void page_table_guest_data_init(struct lg_cpu *cpu)
{
/* We get the kernel address: above this is all kernel memory. */
if (get_user(cpu->lg->kernel_address,
- &cpu->lg->lguest_data->kernel_address)
- /* We tell the Guest that it can't use the top 4MB of virtual
- * addresses used by the Switcher. */
- || put_user(4U*1024*1024, &cpu->lg->lguest_data->reserve_mem)
- || put_user(cpu->lg->pgdirs[0].gpgdir, &cpu->lg->lguest_data->pgdir))
+ &cpu->lg->lguest_data->kernel_address)
+ /* We tell the Guest that it can't use the top 2 or 4 MB
+ * of virtual addresses used by the Switcher. */
+ || put_user(RESERVE_MEM * 1024 * 1024,
+ &cpu->lg->lguest_data->reserve_mem)
+ || put_user(cpu->lg->pgdirs[0].gpgdir,
+ &cpu->lg->lguest_data->pgdir))
kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
/* In flush_user_mappings() we loop from 0 to
* "pgd_index(lg->kernel_address)". This assumes it won't hit the
* Switcher mappings, so check that now. */
+#ifdef CONFIG_X86_PAE
+ if (pgd_index(cpu->lg->kernel_address) == SWITCHER_PGD_INDEX &&
+ pmd_index(cpu->lg->kernel_address) == SWITCHER_PMD_INDEX)
+#else
if (pgd_index(cpu->lg->kernel_address) >= SWITCHER_PGD_INDEX)
+#endif
kill_guest(cpu, "bad kernel address %#lx",
cpu->lg->kernel_address);
}
@@ -708,16 +969,30 @@ void free_guest_pagetable(struct lguest *lg)
void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages)
{
pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);
- pgd_t switcher_pgd;
pte_t regs_pte;
unsigned long pfn;
+#ifdef CONFIG_X86_PAE
+ pmd_t switcher_pmd;
+ pmd_t *pmd_table;
+
+ native_set_pmd(&switcher_pmd, pfn_pmd(__pa(switcher_pte_page) >>
+ PAGE_SHIFT, PAGE_KERNEL_EXEC));
+
+ pmd_table = __va(pgd_pfn(cpu->lg->
+ pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX])
+ << PAGE_SHIFT);
+ native_set_pmd(&pmd_table[SWITCHER_PMD_INDEX], switcher_pmd);
+#else
+ pgd_t switcher_pgd;
+
/* Make the last PGD entry for this Guest point to the Switcher's PTE
* page for this CPU (with appropriate flags). */
switcher_pgd = __pgd(__pa(switcher_pte_page) | __PAGE_KERNEL_EXEC);
cpu->lg->pgdirs[cpu->cpu_pgd].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd;
+#endif
/* We also change the Switcher PTE page. When we're running the Guest,
* we want the Guest's "regs" page to appear where the first Switcher
* page for this CPU is. This is an optimization: when the Switcher
@@ -726,8 +1001,9 @@ void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages)
* page is already mapped there, we don't have to copy them out
* again. */
pfn = __pa(cpu->regs_page) >> PAGE_SHIFT;
- regs_pte = pfn_pte(pfn, __pgprot(__PAGE_KERNEL));
- switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte;
+ native_set_pte(®s_pte, pfn_pte(pfn, PAGE_KERNEL));
+ native_set_pte(&switcher_pte_page[pte_index((unsigned long)pages)],
+ regs_pte);
}
/*:*/
--
1.6.0.4
More information about the Lguest
mailing list