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-rw-r--r--arch/x86/lguest/boot.c36
1 files changed, 22 insertions, 14 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index db832fd65ec..13ee258442a 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -71,7 +71,8 @@
#include <asm/stackprotector.h>
#include <asm/reboot.h> /* for struct machine_ops */
-/*G:010 Welcome to the Guest!
+/*G:010
+ * Welcome to the Guest!
*
* The Guest in our tale is a simple creature: identical to the Host but
* behaving in simplified but equivalent ways. In particular, the Guest is the
@@ -190,15 +191,23 @@ static void lazy_hcall4(unsigned long call,
#endif
/*G:036
- * 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.
-:*/
+ * When lazy mode is turned off, we issue the do-nothing hypercall to
+ * flush any stored calls, and call the generic helper to reset the
+ * per-cpu lazy mode variable.
+ */
static void lguest_leave_lazy_mmu_mode(void)
{
hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0);
paravirt_leave_lazy_mmu();
}
+/*
+ * We also catch the end of context switch; we enter lazy mode for much of
+ * that too, so again we need to flush here.
+ *
+ * (Technically, this is lazy CPU mode, and normally we're in lazy MMU
+ * mode, but unlike Xen, lguest doesn't care about the difference).
+ */
static void lguest_end_context_switch(struct task_struct *next)
{
hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0, 0);
@@ -391,7 +400,7 @@ static void lguest_load_tr_desc(void)
* giant ball of hair. Its entry in the current Intel manual runs to 28 pages.
*
* This instruction even it has its own Wikipedia entry. The Wikipedia entry
- * has been translated into 5 languages. I am not making this up!
+ * has been translated into 6 languages. I am not making this up!
*
* We could get funky here and identify ourselves as "GenuineLguest", but
* instead we just use the real "cpuid" instruction. Then I pretty much turned
@@ -458,7 +467,7 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
/*
* PAE systems can mark pages as non-executable. Linux calls this the
* NX bit. Intel calls it XD (eXecute Disable), AMD EVP (Enhanced
- * Virus Protection). We just switch turn if off here, since we don't
+ * Virus Protection). We just switch it off here, since we don't
* support it.
*/
case 0x80000001:
@@ -520,17 +529,16 @@ static unsigned long lguest_read_cr2(void)
/* See lguest_set_pte() below. */
static bool cr3_changed = false;
+static unsigned long current_cr3;
/*
* cr3 is the current toplevel pagetable page: the principle is the same as
- * cr0. Keep a local copy, and tell the Host when it changes. The only
- * difference is that our local copy is in lguest_data because the Host needs
- * to set it upon our initial hypercall.
+ * cr0. Keep a local copy, and tell the Host when it changes.
*/
static void lguest_write_cr3(unsigned long cr3)
{
- lguest_data.pgdir = cr3;
lazy_hcall1(LHCALL_NEW_PGTABLE, cr3);
+ current_cr3 = cr3;
/* These two page tables are simple, linear, and used during boot */
if (cr3 != __pa(swapper_pg_dir) && cr3 != __pa(initial_page_table))
@@ -539,7 +547,7 @@ static void lguest_write_cr3(unsigned long cr3)
static unsigned long lguest_read_cr3(void)
{
- return lguest_data.pgdir;
+ return current_cr3;
}
/* cr4 is used to enable and disable PGE, but we don't care. */
@@ -641,7 +649,7 @@ static void lguest_write_cr4(unsigned long val)
/*
* The Guest calls this after it has set a second-level entry (pte), ie. to map
- * a page into a process' address space. Wetell the Host the toplevel and
+ * a page into a process' address space. We tell the Host the toplevel and
* address this corresponds to. The Guest uses one pagetable per process, so
* we need to tell the Host which one we're changing (mm->pgd).
*/
@@ -758,7 +766,7 @@ static void lguest_pmd_clear(pmd_t *pmdp)
static void lguest_flush_tlb_single(unsigned long addr)
{
/* Simply set it to zero: if it was not, it will fault back in. */
- lazy_hcall3(LHCALL_SET_PTE, lguest_data.pgdir, addr, 0);
+ lazy_hcall3(LHCALL_SET_PTE, current_cr3, addr, 0);
}
/*
@@ -1140,7 +1148,7 @@ static struct notifier_block paniced = {
static __init char *lguest_memory_setup(void)
{
/*
- *The Linux bootloader header contains an "e820" memory map: the
+ * The Linux bootloader header contains an "e820" memory map: the
* Launcher populated the first entry with our memory limit.
*/
e820_add_region(boot_params.e820_map[0].addr,