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Merge git://github.com/rustyrussell/linux
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* git://github.com/rustyrussell/linux:
  lguest: move process freezing before pending signals check
  lguest: don't allow KVM-detection cpuid.
  lguest: Allow running under paravirt-enabled KVM.
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Linus Torvalds committed Oct 29, 2011
2 parents 2498424 + 0acf000 commit ce94971
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Showing 2 changed files with 18 additions and 8 deletions.
10 changes: 10 additions & 0 deletions arch/x86/lguest/boot.c
Original file line number Diff line number Diff line change
Expand Up @@ -70,6 +70,7 @@
#include <asm/i387.h>
#include <asm/stackprotector.h>
#include <asm/reboot.h> /* for struct machine_ops */
#include <asm/kvm_para.h>

/*G:010
* Welcome to the Guest!
Expand Down Expand Up @@ -455,6 +456,15 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx,
*ax &= 0xFFFFF0FF;
*ax |= 0x00000500;
break;

/*
* This is used to detect if we're running under KVM. We might be,
* but that's a Host matter, not us. So say we're not.
*/
case KVM_CPUID_SIGNATURE:
*bx = *cx = *dx = 0;
break;

/*
* 0x80000000 returns the highest Extended Function, so we futureproof
* like we do above by limiting it to known fields.
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16 changes: 8 additions & 8 deletions drivers/lguest/core.c
Original file line number Diff line number Diff line change
Expand Up @@ -232,6 +232,13 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
}
}

/*
* All long-lived kernel loops need to check with this horrible
* thing called the freezer. If the Host is trying to suspend,
* it stops us.
*/
try_to_freeze();

/* Check for signals */
if (signal_pending(current))
return -ERESTARTSYS;
Expand All @@ -245,13 +252,6 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user)
if (irq < LGUEST_IRQS)
try_deliver_interrupt(cpu, irq, more);

/*
* All long-lived kernel loops need to check with this horrible
* thing called the freezer. If the Host is trying to suspend,
* it stops us.
*/
try_to_freeze();

/*
* Just make absolutely sure the Guest is still alive. One of
* those hypercalls could have been fatal, for example.
Expand Down Expand Up @@ -313,7 +313,7 @@ static int __init init(void)
int err;

/* Lguest can't run under Xen, VMI or itself. It does Tricky Stuff. */
if (paravirt_enabled()) {
if (get_kernel_rpl() != 0) {
printk("lguest is afraid of being a guest\n");
return -EPERM;
}
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