Re: [PATCH try #2] kvm-12 userland guest reboot fix

["Joerg Roedel" <joerg.roedel-5C7GfCeVMHo@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 2376 bytes --]

On Thu, Feb 01, 2007 at 10:25:21AM +0200, Avi Kivity wrote:
> Joerg Roedel wrote:
> >From: Markus Rechberger <markus.rechberger-5C7GfCeVMHo@public.gmane.org>
> >From: Joerg Roedel <joerg.roedel-5C7GfCeVMHo@public.gmane.org>
> >
> >This patch fixes the initialization of the segment registers which
> >solves the triple fault and keyboard controller reset problems in
> >kvm/qemu guests as well as the slow grub menu interaction. The patch
> >should also work on Intel VMX now.
> >  diff -upr kvm-12/qemu/target-i386/helper2.c 
> >kvm-12-reboot-fixed/qemu/target-i386/helper2.c
> >--- kvm-12/qemu/target-i386/helper2.c	2006-12-31 14:31:38.000000000 +0100
> >+++ kvm-12-reboot-fixed/qemu/target-i386/helper2.c	2007-01-23 20:24:42.265987000 +0100
> >@@ -151,6 +151,9 @@ CPUX86State *cpu_x86_init(void)
> > void cpu_reset(CPUX86State *env)
> > {
> >     int i;
> >+    unsigned int flags = DESC_P_MASK |
> >+                         DESC_S_MASK |
> >+                         (2 << DESC_TYPE_SHIFT);
> >      memset(env, 0, offsetof(CPUX86State, breakpoints));
> > @@ -173,9 +176,9 @@ void cpu_reset(CPUX86State *env)
> >     env->tr.flags = DESC_P_MASK;
> >          cpu_x86_load_seg_cache(env, R_CS, 0xf000, 0xffff0000, 0xffff, 0); -    
> >cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffff, 0);
> >-    cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffff, 0);
> >-    cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffff, 0);
> >+    cpu_x86_load_seg_cache(env, R_DS, 0, 0, 0xffff, flags);
> >+    cpu_x86_load_seg_cache(env, R_ES, 0, 0, 0xffff, flags);
> >+    cpu_x86_load_seg_cache(env, R_SS, 0, 0, 0xffff, flags);
> >     cpu_x86_load_seg_cache(env, R_FS, 0, 0, 0xffff, 0);
> >     cpu_x86_load_seg_cache(env, R_GS, 0, 0, 0xffff, 0);
> >  
> 
> This changes core qemu code, which may make merging our code back to qemu more difficult.  
> It also means we need to test with -no-kvm.
> 
> Can you try making load_regs() in qemu-kvm.c detect the case of flags == 0 (perhaps only if 
> cr0.pg == 0) and changing it only then?  It should have the same effect.

I tested the patch with -no-kvm too (with Linux guest) and it worked
without problems. In my opinion it is cleaner to do it cpu_reset but
YMMV. Anyway, here is a patch that implements this fixup in load_regs.
You can choice which patch to apply :)

Joerg

-- 
Joerg Roedel
Operating System Research Center
AMD Saxony LLC & Co. KG

[-- Attachment #2: kvm-12-reboot-fix3.patch --]
[-- Type: text/plain, Size: 3922 bytes --]

diff -upr kvm-12/kernel/vmx.c kvm-12-reboot-fixed/kernel/vmx.c
--- kvm-12/kernel/vmx.c	2007-01-23 11:40:46.000000000 +0100
+++ kvm-12-reboot-fixed/kernel/vmx.c	2007-01-29 15:09:02.620662000 +0100
@@ -781,6 +781,9 @@ static void vmx_set_cr0(struct kvm_vcpu 
  */
 static void vmx_set_cr0_no_modeswitch(struct kvm_vcpu *vcpu, unsigned long cr0)
 {
+	if (!vcpu->rmode.active && !(cr0 & CR0_PE_MASK))
+		enter_rmode(vcpu);
+	
 	vcpu->rmode.active = ((cr0 & CR0_PE_MASK) == 0);
 	update_exception_bitmap(vcpu);
 	vmcs_writel(CR0_READ_SHADOW, cr0);
diff -upr kvm-12/qemu/qemu-kvm.c kvm-12-reboot-fixed/qemu/qemu-kvm.c
--- kvm-12/qemu/qemu-kvm.c	2007-01-23 11:40:46.000000000 +0100
+++ kvm-12-reboot-fixed/qemu/qemu-kvm.c	2007-02-01 17:22:17.511590000 +0100
@@ -124,6 +124,15 @@ static void get_seg(SegmentCache *lhs, c
 	| (rhs->avl * DESC_AVL_MASK);
 }
 
+/* the reset values of qemu are not compatible to SVM
+ * this function is used to fix the segment descriptor values */
+static void fix_realmode_dataseg(struct kvm_segment *seg)
+{
+	seg->type = 0x02;
+	seg->present = 1;
+	seg->s = 1;
+}
+
 static void load_regs(CPUState *env)
 {
     struct kvm_regs regs;
@@ -182,6 +191,12 @@ static void load_regs(CPUState *env)
 			(sregs.cs.selector & 3);
 		sregs.ss.dpl = sregs.ss.selector & 3;
 	    }
+
+	    if (!(env->cr[0] & CR0_PG_MASK)) {
+		    fix_realmode_dataseg(&sregs.ds);
+		    fix_realmode_dataseg(&sregs.es);
+		    fix_realmode_dataseg(&sregs.ss);
+	    }
     }
 
     set_seg(&sregs.tr, &env->tr);
@@ -582,6 +597,12 @@ static int kvm_halt(void *opaque, int vc
 
     return 1;
 }
+
+static int kvm_shutdown(void *opaque, int vcpu)
+{
+    qemu_system_reset_request();
+    return 1;
+}
  
 static struct kvm_callbacks qemu_kvm_ops = {
     .cpuid = kvm_cpuid,
@@ -601,6 +622,7 @@ static struct kvm_callbacks qemu_kvm_ops
     .writel = kvm_writel,
     .writeq = kvm_writeq,
     .halt  = kvm_halt,
+    .shutdown = kvm_shutdown,
     .io_window = kvm_io_window,
     .try_push_interrupts = try_push_interrupts,
     .post_kvm_run = post_kvm_run,
diff -upr kvm-12/qemu/vl.c kvm-12-reboot-fixed/qemu/vl.c
--- kvm-12/qemu/vl.c	2007-01-07 13:58:54.000000000 +0100
+++ kvm-12-reboot-fixed/qemu/vl.c	2007-01-23 20:11:53.772182000 +0100
@@ -5281,6 +5281,10 @@ int main_loop(void)
             if (reset_requested) {
                 reset_requested = 0;
                 qemu_system_reset();
+#ifdef USE_KVM
+		if (kvm_allowed)
+			kvm_load_registers(env);
+#endif
                 ret = EXCP_INTERRUPT;
             }
             if (powerdown_requested) {
diff -upr kvm-12/user/kvmctl.c kvm-12-reboot-fixed/user/kvmctl.c
--- kvm-12/user/kvmctl.c	2006-12-31 14:31:38.000000000 +0100
+++ kvm-12-reboot-fixed/user/kvmctl.c	2007-01-23 19:48:18.111267000 +0100
@@ -522,6 +522,11 @@ static int handle_halt(kvm_context_t kvm
 	return kvm->callbacks->halt(kvm->opaque, kvm_run->vcpu);
 }
 
+static int handle_shutdown(kvm_context_t kvm, struct kvm_run *kvm_run)
+{
+	return kvm->callbacks->shutdown(kvm->opaque, kvm_run->vcpu);
+}
+
 int try_push_interrupts(kvm_context_t kvm)
 {
 	return kvm->callbacks->try_push_interrupts(kvm->opaque);
@@ -594,6 +599,9 @@ again:
 			break;
 		case KVM_EXIT_IRQ_WINDOW_OPEN:
 			break;
+		case KVM_EXIT_SHUTDOWN:
+			r = handle_shutdown(kvm, &kvm_run);
+			break;
 		default:
 			fprintf(stderr, "unhandled vm exit: 0x%x\n", kvm_run.exit_reason);
 			kvm_show_regs(kvm, vcpu);
diff -upr kvm-12/user/kvmctl.h kvm-12-reboot-fixed/user/kvmctl.h
--- kvm-12/user/kvmctl.h	2006-12-31 14:31:38.000000000 +0100
+++ kvm-12-reboot-fixed/user/kvmctl.h	2007-01-23 18:25:32.758594000 +0100
@@ -59,6 +59,7 @@ struct kvm_callbacks {
 	 * on the host CPU.
 	 */
     int (*halt)(void *opaque, int vcpu);
+    int (*shutdown)(void *opaque, int vcpu);
     int (*io_window)(void *opaque);
     int (*try_push_interrupts)(void *opaque);
     void (*post_kvm_run)(void *opaque, struct kvm_run *kvm_run);

[-- Attachment #3: Type: text/plain, Size: 374 bytes --]

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier.
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

[-- Attachment #4: Type: text/plain, Size: 186 bytes --]

_______________________________________________
kvm-devel mailing list
kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
https://lists.sourceforge.net/lists/listinfo/kvm-devel