Mailing List Archive

# HG changeset patch
# User kaf24@firebug.cl.cam.ac.uk
# Node ID b7e88c83b2a0991590e5d46531d487a3356cd4fb
# Parent c96ea9ebcd298c30bc251cce14b78ca8cb3dd69e
More code cleanups, mainly to do_iret() implementations.

Signed-off-by: Keir Fraser <keir@xensource.com>

diff -r c96ea9ebcd29 -r b7e88c83b2a0 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Wed Jan 11 18:26:03 2006
+++ b/xen/arch/x86/domain.c Wed Jan 11 18:44:54 2006
@@ -480,14 +480,6 @@

#ifdef __x86_64__

-void toggle_guest_mode(struct vcpu *v)
-{
- v->arch.flags ^= TF_kernel_mode;
- __asm__ __volatile__ ( "swapgs" );
- update_pagetables(v);
- write_ptbase(v);
-}
-
#define loadsegment(seg,value) ({ \
int __r = 1; \
__asm__ __volatile__ ( \
diff -r c96ea9ebcd29 -r b7e88c83b2a0 xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Wed Jan 11 18:26:03 2006
+++ b/xen/arch/x86/mm.c Wed Jan 11 18:44:54 2006
@@ -297,7 +297,6 @@

#if defined(__x86_64__)
/* If in user mode, switch to kernel mode just to read LDT mapping. */
- extern void toggle_guest_mode(struct vcpu *);
int user_mode = !(v->arch.flags & TF_kernel_mode);
#define TOGGLE_MODE() if ( user_mode ) toggle_guest_mode(v)
#elif defined(__i386__)
@@ -2971,7 +2970,6 @@

#ifdef CONFIG_X86_64
struct vcpu *v = current;
- extern void toggle_guest_mode(struct vcpu *);
int user_mode = !(v->arch.flags & TF_kernel_mode);
#endif

diff -r c96ea9ebcd29 -r b7e88c83b2a0 xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c Wed Jan 11 18:26:03 2006
+++ b/xen/arch/x86/traps.c Wed Jan 11 18:44:54 2006
@@ -596,7 +596,6 @@
u16 x;
#if defined(__x86_64__)
/* If in user mode, switch to kernel mode just to read I/O bitmap. */
- extern void toggle_guest_mode(struct vcpu *);
int user_mode = !(v->arch.flags & TF_kernel_mode);
#define TOGGLE_MODE() if ( user_mode ) toggle_guest_mode(v)
#elif defined(__i386__)
diff -r c96ea9ebcd29 -r b7e88c83b2a0 xen/arch/x86/x86_32/traps.c
--- a/xen/arch/x86/x86_32/traps.c Wed Jan 11 18:26:03 2006
+++ b/xen/arch/x86/x86_32/traps.c Wed Jan 11 18:44:54 2006
@@ -157,38 +157,37 @@
__asm__ __volatile__ ( "hlt" );
}

+static inline void pop_from_guest_stack(
+ void *dst, struct cpu_user_regs *regs, unsigned int bytes)
+{
+ if ( unlikely(copy_from_user(dst, (void __user *)regs->esp, bytes)) )
+ domain_crash_synchronous();
+ regs->esp += bytes;
+}
+
asmlinkage unsigned long do_iret(void)
{
struct cpu_user_regs *regs = guest_cpu_user_regs();

- /* Restore EAX (clobbered by hypercall). */
- if ( copy_from_user(&regs->eax, (void __user *)regs->esp, 4) )
+ /* Pop and restore EAX (clobbered by hypercall). */
+ pop_from_guest_stack(&regs->eax, regs, 4);
+
+ /* Pop and restore EFLAGS, CS and EIP. */
+ pop_from_guest_stack(&regs->eip, regs, 12);
+
+ if ( VM86_MODE(regs) )
+ {
+ /* Return to VM86 mode: pop and restore ESP,SS,ES,DS,FS and GS. */
+ pop_from_guest_stack(&regs->esp, regs, 24);
+ }
+ else if ( RING_0(regs) )
+ {
domain_crash_synchronous();
- regs->esp += 4;
-
- /* Restore EFLAGS, CS and EIP. */
- if ( copy_from_user(&regs->eip, (void __user *)regs->esp, 12) )
- domain_crash_synchronous();
-
- if ( VM86_MODE(regs) )
- {
- /* Return to VM86 mode: restore ESP,SS,ES,DS,FS and GS. */
- if(copy_from_user(&regs->esp, (void __user *)(regs->esp+12), 24))
- domain_crash_synchronous();
- }
- else if ( RING_0(regs) )
- {
- domain_crash_synchronous();
- }
- else if ( RING_1(regs) ) {
- /* Return to ring 1: pop EFLAGS,CS and EIP. */
- regs->esp += 12;
- }
- else
- {
- /* Return to ring 2/3: restore ESP and SS. */
- if ( copy_from_user(&regs->esp, (void __user *)(regs->esp+12), 8) )
- domain_crash_synchronous();
+ }
+ else if ( !RING_1(regs) )
+ {
+ /* Return to ring 2/3: pop and restore ESP and SS. */
+ pop_from_guest_stack(&regs->esp, regs, 8);
}

/* Fixup EFLAGS. */
diff -r c96ea9ebcd29 -r b7e88c83b2a0 xen/arch/x86/x86_64/traps.c
--- a/xen/arch/x86/x86_64/traps.c Wed Jan 11 18:26:03 2006
+++ b/xen/arch/x86/x86_64/traps.c Wed Jan 11 18:44:54 2006
@@ -114,7 +114,13 @@
__asm__ __volatile__ ( "hlt" );
}

-extern void toggle_guest_mode(struct vcpu *);
+void toggle_guest_mode(struct vcpu *v)
+{
+ v->arch.flags ^= TF_kernel_mode;
+ __asm__ __volatile__ ( "swapgs" );
+ update_pagetables(v);
+ write_ptbase(v);
+}

long do_iret(void)
{
@@ -122,13 +128,17 @@
struct iret_context iret_saved;
struct vcpu *v = current;

- if ( unlikely(copy_from_user(&iret_saved, (void *)regs->rsp, sizeof(iret_saved))) ||
- unlikely(pagetable_get_paddr(v->arch.guest_table_user) == 0) )
- return -EFAULT;
-
- /* Returning to user mode. */
- if ( (iret_saved.cs & 0x03) == 3 )
+ if ( unlikely(copy_from_user(&iret_saved, (void *)regs->rsp,
+ sizeof(iret_saved))) )
+ domain_crash_synchronous();
+
+ /* Returning to user mode? */
+ if ( (iret_saved.cs & 3) == 3 )
+ {
+ if ( unlikely(pagetable_get_paddr(v->arch.guest_table_user) == 0) )
+ return -EFAULT;
toggle_guest_mode(v);
+ }

regs->rip = iret_saved.rip;
regs->cs = iret_saved.cs | 3; /* force guest privilege */
diff -r c96ea9ebcd29 -r b7e88c83b2a0 xen/include/asm-x86/domain.h
--- a/xen/include/asm-x86/domain.h Wed Jan 11 18:26:03 2006
+++ b/xen/include/asm-x86/domain.h Wed Jan 11 18:44:54 2006
@@ -46,7 +46,10 @@
struct vcpu_maphash vcpu_maphash[MAX_VIRT_CPUS];
};

-extern void mapcache_init(struct domain *d);
+extern void mapcache_init(struct domain *);
+
+/* x86/64: toggle guest between kernel and user modes. */
+extern void toggle_guest_mode(struct vcpu *);

struct arch_domain
{

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