[Xen-changelog] This patch fixes a bug where raise_softirq(SCHEDULE_SOFTIRQ) is called

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 76f4c7ea7602cc6c44e55a312983840aa0f222a8
# Parent  f71bb61e0500decbe074239f21cca9be2c6e210e
This patch fixes a bug where raise_softirq(SCHEDULE_SOFTIRQ) is called
upon a hlt instruction from a VMX guest, causing repeated VMExits when
the guest is idle. At the same time, it disables the monitor/mwait
feature as it's not feasible to implement for vcpu.

Signed-off-by: Xiaofeng Ling <xiaofeng.ling@xxxxxxxxx>
Signed-off-by: Asit Mallick <asit.k.mallick@xxxxxxxxx>
Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx>

diff -r f71bb61e0500 -r 76f4c7ea7602 xen/arch/x86/vmx.c
--- a/xen/arch/x86/vmx.c        Wed Sep 21 16:36:46 2005
+++ b/xen/arch/x86/vmx.c        Wed Sep 21 16:58:55 2005
@@ -471,6 +471,8 @@
         }
 #endif
 
+        /* Unsupportable for virtualised CPUs. */
+        clear_bit(X86_FEATURE_MWAIT & 31, &ecx);
     }
 
     regs->eax = (unsigned long) eax;
@@ -1461,7 +1463,7 @@
  */
 void vmx_vmexit_do_hlt(void)
 {
-    raise_softirq(SCHEDULE_SOFTIRQ);
+    do_block();
 }
 
 static inline void vmx_vmexit_do_extint(struct cpu_user_regs *regs)
@@ -1509,12 +1511,6 @@
         do_IRQ(regs);
         break;
     }
-}
-
-volatile unsigned long do_mwait_count;
-static inline void vmx_vmexit_do_mwait(void)
-{
-    raise_softirq(SCHEDULE_SOFTIRQ);
 }
 
 #define BUF_SIZ     256
@@ -1798,9 +1794,7 @@
         __update_guest_eip(inst_len);
         break;
     case EXIT_REASON_MWAIT_INSTRUCTION:
-        __get_instruction_length(inst_len);
-        __update_guest_eip(inst_len);
-        vmx_vmexit_do_mwait();
+        __vmx_bug(&regs);
         break;
     default:
         __vmx_bug(&regs);       /* should not happen */
diff -r f71bb61e0500 -r 76f4c7ea7602 xen/arch/x86/vmx_intercept.c
--- a/xen/arch/x86/vmx_intercept.c      Wed Sep 21 16:36:46 2005
+++ b/xen/arch/x86/vmx_intercept.c      Wed Sep 21 16:58:55 2005
@@ -28,6 +28,7 @@
 #include <xen/sched.h>
 #include <asm/current.h>
 #include <io_ports.h>
+#include <xen/event.h>
 
 #ifdef CONFIG_VMX
 
@@ -205,6 +206,7 @@
     /* Set the pending intr bit, and send evtchn notification to myself. */
     if (test_and_set_bit(vpit->vector, vpit->intr_bitmap))
         vpit->pending_intr_nr++; /* already set, then count the pending intr */
+    evtchn_set_pending(vpit->v, iopacket_port(vpit->v->domain));
 
     /* pick up missed timer tick */
     if ( missed_ticks > 0 ) {
@@ -281,6 +283,7 @@
         }
 
         vpit->intr_bitmap = intr;
+        vpit->v = d;
 
         vpit->scheduled = NOW() + vpit->period;
         set_ac_timer(&vpit->pit_timer, vpit->scheduled);
diff -r f71bb61e0500 -r 76f4c7ea7602 xen/include/asm-x86/vmx_virpit.h
--- a/xen/include/asm-x86/vmx_virpit.h  Wed Sep 21 16:36:46 2005
+++ b/xen/include/asm-x86/vmx_virpit.h  Wed Sep 21 16:58:55 2005
@@ -35,8 +35,8 @@
 
     unsigned int count;  /* the 16 bit channel count */
     unsigned int init_val; /* the init value for the counter */
-
-} ;
+    struct vcpu *v;
+};
 
 /* to hook the ioreq packet to get the PIT initializaiton info */
 extern void vmx_hooks_assist(struct vcpu *d);

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