Re: [PATCH] 2/2: Fall back to plain Qemu if KVM is not present, report errors from libkvm

Simon Kagstrom
2006-11-14T13:39:48Z

At Tue, 14 Nov 2006 15:24:35 +0200,
Avi Kivity wrote:
>
> Simon Kagstrom wrote:
> > diff -u ../orig/kvm-2/qemu/vl.c qemu/vl.c
> > --- ../orig/kvm-2/qemu/vl.c 2006-11-05 10:18:52.000000000 +0100
> > +++ qemu/vl.c 2006-11-14 13:56:32.000000000 +0100
> > @@ -5706,6 +5706,10 @@
> >
> > nb_nics = 0;
> > /* default mac address of the first network interface */
> > +#if USE_KVM
> > + if (kvm_qemu_init() < 0)
> > + kvm_allowed = 0;
> > +#endif
> >
>
> Doesn't this bit will initialize kvm even if the user specified -no-kvm?

Yes. Maybe I misunderstood you, but this is how I understood your
comments.

Sorry for spamming the list with patches. I'll send yet another
one. This will check and possibly disable KVM after the command-line
options have been parsed. If -no-kvm has been given, nothing will
happen.

Hopefully this will be the final patch! :-)

// Simon

diff -u ../orig/kvm-2/qemu/qemu-kvm.c qemu/qemu-kvm.c
--- ../orig/kvm-2/qemu/qemu-kvm.c 2006-11-05 10:18:52.000000000 +0100
+++ qemu/qemu-kvm.c 2006-11-14 13:56:35.000000000 +0100
@@ -450,10 +450,30 @@
.io_window = kvm_io_window,
};

-void kvm_qemu_init()
+int kvm_qemu_init()
{
+ /* Try to initialize kvm */
kvm_context = kvm_init(&qemu_kvm_ops, saved_env);
- kvm_create(kvm_context, phys_ram_size, (void**)&phys_ram_base);
+ if (!kvm_context) {
+ return -1;
+ }
+
+ return 0;
+}
+
+int kvm_qemu_create_context(void)
+{
+ if (kvm_create(kvm_context, phys_ram_size, (void**)&phys_ram_base) < 0) {
+ kvm_qemu_destroy();
+ return -1;
+ }
+
+ return 0;
+}
+
+void kvm_qemu_destroy(void)
+{
+ kvm_finalize(kvm_context);
}

int kvm_update_debugger(CPUState *env)
diff -u ../orig/kvm-2/qemu/qemu-kvm.h qemu/qemu-kvm.h
--- ../orig/kvm-2/qemu/qemu-kvm.h 2006-10-16 11:01:02.000000000 +0200
+++ qemu/qemu-kvm.h 2006-11-14 13:55:56.000000000 +0100
@@ -3,7 +3,9 @@

#include "kvmctl.h"

-void kvm_qemu_init(void);
+int kvm_qemu_init(void);
+int kvm_qemu_create_context(void);
+void kvm_qemu_destroy(void);
void kvm_load_registers(CPUState *env);
int kvm_cpu_exec(CPUState *env);
int kvm_update_debugger(CPUState *env);
diff -u ../orig/kvm-2/qemu/vl.c qemu/vl.c
--- ../orig/kvm-2/qemu/vl.c 2006-11-05 10:18:52.000000000 +0100
+++ qemu/vl.c 2006-11-14 14:34:18.000000000 +0100
@@ -6054,6 +6054,15 @@
}
}

+#if USE_KVM
+ if (kvm_allowed) {
+ if (kvm_qemu_init() < 0) {
+ fprintf(stderr, "Could not initialize KVM, will disable KVM support\n");
+ kvm_allowed = 0;
+ }
+ }
+#endif
+
#ifdef USE_KQEMU
if (smp_cpus > 1)
kqemu_allowed = 0;
@@ -6099,11 +6108,15 @@
}

/* init the memory */
-#if USE_KVM
phys_ram_size = ram_size + vga_ram_size + bios_size;
+#if USE_KVM
+ /* Initialize kvm */
if (kvm_allowed) {
phys_ram_size += KVM_EXTRA_PAGES * 4096;
- kvm_qemu_init();
+ if (kvm_qemu_create_context() < 0) {
+ fprintf(stderr, "Could not create KVM context\n");
+ exit(1);
+ }
} else {
phys_ram_base = qemu_vmalloc(phys_ram_size);
if (!phys_ram_base) {
@@ -6112,7 +6125,6 @@
}
}
#else
- phys_ram_size = ram_size + vga_ram_size + bios_size;
phys_ram_base = qemu_vmalloc(phys_ram_size);
if (!phys_ram_base) {
fprintf(stderr, "Could not allocate physical memory\n");