# HG changeset patch
# User Ian.Campbell@xxxxxxxxxxxxx
# Node ID 06ab200a9e23b1820197e3ae4a101e5b7590041b
# Parent fe4d06b15a36efe0f7a0926f7ba761747ee43d1a
Pass NMIs to DOM0 via a dedicated callback, Xen x86_64 support.
Handle NMI interrupts and dispatch to dom0 on x86_64.
Renames the switch_to_user hypercall to iret. Extend the semantics to
include returns to guest/kernel if CS indicates ring 1. Retain the old
semantics of returning to guest/user if CS indicates ring3.
Plumb in nmi_op hypercall to generic code.
Signed-off-by: Ian Campbell <Ian.Campbell@xxxxxxxxxxxxx>
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Wed Jan 11 15:52:12 2006
+++ b/xen/arch/x86/domain.c Wed Jan 11 15:52:33 2006
@@ -659,35 +659,6 @@
percpu_ctxt[smp_processor_id()].dirty_segment_mask = dirty_segment_mask;
}
-long do_switch_to_user(void)
-{
- struct cpu_user_regs *regs = guest_cpu_user_regs();
- struct switch_to_user stu;
- struct vcpu *v = current;
-
- if ( unlikely(copy_from_user(&stu, (void *)regs->rsp, sizeof(stu))) ||
- unlikely(pagetable_get_paddr(v->arch.guest_table_user) == 0) )
- return -EFAULT;
-
- toggle_guest_mode(v);
-
- regs->rip = stu.rip;
- regs->cs = stu.cs | 3; /* force guest privilege */
- regs->rflags = (stu.rflags & ~(EF_IOPL|EF_VM)) | EF_IE;
- regs->rsp = stu.rsp;
- regs->ss = stu.ss | 3; /* force guest privilege */
-
- if ( !(stu.flags & VGCF_IN_SYSCALL) )
- {
- regs->entry_vector = 0;
- regs->r11 = stu.r11;
- regs->rcx = stu.rcx;
- }
-
- /* Saved %rax gets written back to regs->rax in entry.S. */
- return stu.rax;
-}
-
#define switch_kernel_stack(_n,_c) ((void)0)
#elif defined(__i386__)
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/arch/x86/x86_64/asm-offsets.c
--- a/xen/arch/x86/x86_64/asm-offsets.c Wed Jan 11 15:52:12 2006
+++ b/xen/arch/x86/x86_64/asm-offsets.c Wed Jan 11 15:52:33 2006
@@ -65,6 +65,10 @@
arch.guest_context.syscall_callback_eip);
OFFSET(VCPU_kernel_sp, struct vcpu,
arch.guest_context.kernel_sp);
+ OFFSET(VCPU_flags, struct vcpu, vcpu_flags);
+ OFFSET(VCPU_nmi_addr, struct vcpu, nmi_addr);
+ DEFINE(_VCPUF_nmi_pending, _VCPUF_nmi_pending);
+ DEFINE(_VCPUF_nmi_masked, _VCPUF_nmi_masked);
BLANK();
OFFSET(VCPUINFO_upcall_pending, vcpu_info_t, evtchn_upcall_pending);
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/arch/x86/x86_64/entry.S
--- a/xen/arch/x86/x86_64/entry.S Wed Jan 11 15:52:12 2006
+++ b/xen/arch/x86/x86_64/entry.S Wed Jan 11 15:52:33 2006
@@ -171,7 +171,9 @@
leaq irq_stat(%rip),%rcx
testl $~0,(%rcx,%rax,1)
jnz process_softirqs
-/*test_guest_events:*/
+ btr $_VCPUF_nmi_pending,VCPU_flags(%rbx)
+ jc process_nmi
+test_guest_events:
movq VCPU_vcpu_info(%rbx),%rax
testb $0xFF,VCPUINFO_upcall_mask(%rax)
jnz restore_all_guest
@@ -322,6 +324,23 @@
call do_softirq
jmp test_all_events
+ ALIGN
+/* %rbx: struct vcpu */
+process_nmi:
+ movq VCPU_nmi_addr(%rbx),%rax
+ test %rax,%rax
+ jz test_all_events
+ bts $_VCPUF_nmi_masked,VCPU_flags(%rbx)
+ jc 1f
+ sti
+ leaq VCPU_trap_bounce(%rbx),%rdx
+ movq %rax,TRAPBOUNCE_eip(%rdx)
+ movw $(TBF_INTERRUPT|TBF_SLOW_IRET),TRAPBOUNCE_flags(%rdx)
+ call create_bounce_frame
+ jmp test_all_events
+1: bts $_VCPUF_nmi_pending,VCPU_flags(%rbx)
+ jmp test_guest_events
+
/* CREATE A BASIC EXCEPTION FRAME ON GUEST OS STACK: */
/* { RCX, R11, [DS-GS,] [CR2,] [ERRCODE,] RIP, CS, RFLAGS, RSP, SS } */
/* %rdx: trap_bounce, %rbx: struct vcpu */
@@ -339,6 +358,9 @@
1: /* In kernel context already: push new frame at existing %rsp. */
movq UREGS_rsp+8(%rsp),%rsi
andb $0xfc,UREGS_cs+8(%rsp) # Indicate kernel context to guest.
+ testw $(TBF_SLOW_IRET),TRAPBOUNCE_flags(%rdx)
+ jz 2f
+ orb $0x01,UREGS_cs+8(%rsp)
2: andq $~0xf,%rsi # Stack frames are 16-byte aligned.
movq $HYPERVISOR_VIRT_START,%rax
cmpq %rax,%rsi
@@ -569,7 +591,7 @@
SAVE_ALL
movq %rsp,%rdi
call do_nmi
- jmp restore_all_xen
+ jmp ret_from_intr
do_arch_sched_op:
# Ensure we return success even if we return via schedule_tail()
@@ -626,11 +648,12 @@
.quad do_grant_table_op /* 20 */
.quad do_vm_assist
.quad do_update_va_mapping_otherdomain
- .quad do_switch_to_user
+ .quad do_iret
.quad do_vcpu_op
.quad do_set_segment_base /* 25 */
.quad do_mmuext_op
.quad do_acm_op
+ .quad do_nmi_op
.rept NR_hypercalls-((.-hypercall_table)/4)
.quad do_ni_hypercall
.endr
@@ -659,11 +682,12 @@
.byte 3 /* do_grant_table_op */ /* 20 */
.byte 2 /* do_vm_assist */
.byte 4 /* do_update_va_mapping_otherdomain */
- .byte 0 /* do_switch_to_user */
+ .byte 0 /* do_iret */
.byte 3 /* do_vcpu_op */
.byte 2 /* do_set_segment_base */ /* 25 */
.byte 4 /* do_mmuext_op */
.byte 1 /* do_acm_op */
+ .byte 2 /* do_nmi_op */
.rept NR_hypercalls-(.-hypercall_args_table)
.byte 0 /* do_ni_hypercall */
.endr
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/arch/x86/x86_64/traps.c
--- a/xen/arch/x86/x86_64/traps.c Wed Jan 11 15:52:12 2006
+++ b/xen/arch/x86/x86_64/traps.c Wed Jan 11 15:52:33 2006
@@ -12,6 +12,7 @@
#include <asm/current.h>
#include <asm/flushtlb.h>
#include <asm/msr.h>
+#include <asm/shadow.h>
#include <asm/vmx.h>
void show_registers(struct cpu_user_regs *regs)
@@ -113,6 +114,42 @@
__asm__ __volatile__ ( "hlt" );
}
+extern void toggle_guest_mode(struct vcpu *);
+
+long do_iret(void)
+{
+ struct cpu_user_regs *regs = guest_cpu_user_regs();
+ 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)
+ toggle_guest_mode(v);
+
+ regs->rip = iret_saved.rip;
+ regs->cs = iret_saved.cs | 3; /* force guest privilege */
+ regs->rflags = (iret_saved.rflags & ~(EF_IOPL|EF_VM)) | EF_IE;
+ regs->rsp = iret_saved.rsp;
+ regs->ss = iret_saved.ss | 3; /* force guest privilege */
+
+ if ( !(iret_saved.flags & VGCF_IN_SYSCALL) )
+ {
+ regs->entry_vector = 0;
+ regs->r11 = iret_saved.r11;
+ regs->rcx = iret_saved.rcx;
+ }
+
+ /* No longer in NMI context */
+ clear_bit(_VCPUF_nmi_masked, ¤t->vcpu_flags);
+
+ /* Saved %rax gets written back to regs->rax in entry.S. */
+ return iret_saved.rax;
+}
+
asmlinkage void syscall_enter(void);
void __init percpu_traps_init(void)
{
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/include/asm-x86/processor.h
--- a/xen/include/asm-x86/processor.h Wed Jan 11 15:52:12 2006
+++ b/xen/include/asm-x86/processor.h Wed Jan 11 15:52:33 2006
@@ -123,6 +123,7 @@
#define TBF_EXCEPTION_ERRCODE 2
#define TBF_INTERRUPT 8
#define TBF_FAILSAFE 16
+#define TBF_SLOW_IRET 32
/* 'arch_vcpu' flags values */
#define _TF_kernel_mode 0
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/include/public/arch-x86_64.h
--- a/xen/include/public/arch-x86_64.h Wed Jan 11 15:52:12 2006
+++ b/xen/include/public/arch-x86_64.h Wed Jan 11 15:52:33 2006
@@ -88,11 +88,20 @@
#define SEGBASE_GS_USER_SEL 3 /* Set user %gs specified in base[15:0] */
/*
- * int HYPERVISOR_switch_to_user(void)
+ * int HYPERVISOR_iret(void)
* All arguments are on the kernel stack, in the following format.
* Never returns if successful. Current kernel context is lost.
+ * The saved CS is mapped as follows:
+ * RING0 -> RING3 kernel mode.
+ * RING1 -> RING3 kernel mode.
+ * RING2 -> RING3 kernel mode.
+ * RING3 -> RING3 user mode.
+ * However RING0 indicates that the guest kernel should return to iteself
+ * directly with
+ * orb $3,1*8(%rsp)
+ * iretq
* If flags contains VGCF_IN_SYSCALL:
- * Restore RAX, RIP, RFLAGS, RSP.
+ * Restore RAX, RIP, RFLAGS, RSP.
* Discard R11, RCX, CS, SS.
* Otherwise:
* Restore RAX, R11, RCX, CS:RIP, RFLAGS, SS:RSP.
@@ -100,10 +109,17 @@
*/
/* Guest exited in SYSCALL context? Return to guest with SYSRET? */
#define VGCF_IN_SYSCALL (1<<8)
+struct iret_context {
+ /* Top of stack (%rsp at point of hypercall). */
+ uint64_t rax, r11, rcx, flags, rip, cs, rflags, rsp, ss;
+ /* Bottom of iret stack frame. */
+};
+/* For compatibility with HYPERVISOR_switch_to_user which is the old
+ * name for HYPERVISOR_iret */
struct switch_to_user {
/* Top of stack (%rsp at point of hypercall). */
uint64_t rax, r11, rcx, flags, rip, cs, rflags, rsp, ss;
- /* Bottom of switch_to_user stack frame. */
+ /* Bottom of iret stack frame. */
};
/*
diff -r fe4d06b15a36 -r 06ab200a9e23 xen/include/public/xen.h
--- a/xen/include/public/xen.h Wed Jan 11 15:52:12 2006
+++ b/xen/include/public/xen.h Wed Jan 11 15:52:33 2006
@@ -53,9 +53,9 @@
#define __HYPERVISOR_grant_table_op 20
#define __HYPERVISOR_vm_assist 21
#define __HYPERVISOR_update_va_mapping_otherdomain 22
-#define __HYPERVISOR_iret 23 /* x86/32 only */
+#define __HYPERVISOR_iret 23 /* x86 only */
#define __HYPERVISOR_switch_vm86 23 /* x86/32 only (obsolete name) */
-#define __HYPERVISOR_switch_to_user 23 /* x86/64 only */
+#define __HYPERVISOR_switch_to_user 23 /* x86/64 only (obsolete name) */
#define __HYPERVISOR_vcpu_op 24
#define __HYPERVISOR_set_segment_base 25 /* x86/64 only */
#define __HYPERVISOR_mmuext_op 26
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