[Bug that was found by my previous patch]
This patch allows things like modules, which don't have a direct
__pa(EIP) mapping to do emulated instructions.
Sure, the emulated instruction probably should be a paravirt_op, but
this patch lets you at least boot a kernel that has modules needing
emulated instructions.
Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]>
Index: linux-2.6.21-rc5-mm2/drivers/lguest/core.c
===================================================================
--- linux-2.6.21-rc5-mm2.orig/drivers/lguest/core.c
+++ linux-2.6.21-rc5-mm2/drivers/lguest/core.c
@@ -160,11 +160,14 @@ static int emulate_insn(struct lguest *l
{
u8 insn;
unsigned int insnlen = 0, in = 0, shift = 0;
- unsigned long physaddr = guest_pa(lg, lg->regs->eip);
+ unsigned long physaddr = lguest_find_guest_paddr(lg, lg->regs->eip);
- /* This only works for addresses in linear mapping... */
- if (lg->regs->eip < lg->page_offset)
+ /* FIXME: Handle physaddr's that crosses pages (modules are in VM) */
+
+ /* did we actually find the physaddr? */
+ if (physaddr == (unsigned long)-1UL)
return 0;
+
lgread(lg, &insn, physaddr, 1);
/* Operand size prefix means it's actually for ax. */
Index: linux-2.6.21-rc5-mm2/drivers/lguest/lg.h
===================================================================
--- linux-2.6.21-rc5-mm2.orig/drivers/lguest/lg.h
+++ linux-2.6.21-rc5-mm2/drivers/lguest/lg.h
@@ -218,6 +218,7 @@ void guest_set_pte(struct lguest *lg, un
void map_hypervisor_in_guest(struct lguest *lg, struct lguest_pages *pages);
int demand_page(struct lguest *info, unsigned long cr2, int write);
void pin_page(struct lguest *lg, unsigned long vaddr);
+unsigned long lguest_find_guest_paddr(struct lguest *lg, unsigned long vaddr);
/* lguest_user.c: */
int lguest_device_init(void);
Index: linux-2.6.21-rc5-mm2/drivers/lguest/page_tables.c
===================================================================
--- linux-2.6.21-rc5-mm2.orig/drivers/lguest/page_tables.c
+++ linux-2.6.21-rc5-mm2/drivers/lguest/page_tables.c
@@ -105,6 +105,25 @@ static spte_t gpte_to_spte(struct lguest
return spte;
}
+unsigned long lguest_find_guest_paddr(struct lguest *lg, unsigned long vaddr)
+{
+ gpgd_t gpgd;
+ gpte_t gpte;
+ unsigned long gpte_ptr;
+
+ gpgd = mkgpgd(lgread_u32(lg, gpgd_addr(lg, vaddr)));
+ if (!(gpgd.flags & _PAGE_PRESENT))
+ return -1;
+
+ gpte_ptr = gpte_addr(lg, gpgd, vaddr);
+ gpte = mkgpte(lgread_u32(lg, gpte_ptr));
+
+ if (!(gpte.flags & _PAGE_PRESENT))
+ return -1;
+
+ return (gpte.pfn << PAGE_SHIFT) | (vaddr & (PAGE_SIZE-1));
+}
+
/* FIXME: We hold reference to pages, which prevents them from being
swapped. It'd be nice to have a callback when Linux wants to swap out. */
-
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