On Thu, Feb 21, 2008 at 11:54:00AM -0800, Yinghai Lu wrote:
> On Thu, Feb 21, 2008 at 6:50 AM, Joerg Roedel <[EMAIL PROTECTED]> wrote:
> > Inside a KVM virtual machine the MTRRs are usually blank. This confuses
> > Linux
> > and causes a warning message at boot. This patch removes that warning
> > message
> > when running Linux as a KVM guest.
> >
> > Signed-off-by: Joerg Roedel <[EMAIL PROTECTED]>
> > ---
> > arch/x86/kernel/cpu/mtrr/main.c | 7 +++++--
> > 1 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/kernel/cpu/mtrr/main.c
> > b/arch/x86/kernel/cpu/mtrr/main.c
> > index b6e136f..47e624c 100644
> > --- a/arch/x86/kernel/cpu/mtrr/main.c
> > +++ b/arch/x86/kernel/cpu/mtrr/main.c
> > @@ -43,6 +43,7 @@
> > #include <asm/uaccess.h>
> > #include <asm/processor.h>
> > #include <asm/msr.h>
> > +#include <asm/kvm_para.h>
> > #include "mtrr.h"
> >
> > u32 num_var_ranges = 0;
> > @@ -687,12 +688,14 @@ int __init mtrr_trim_uncached_memory(unsigned long
> > end_pfn)
> > }
> >
> > /* kvm/qemu doesn't have mtrr set right, don't trim them all */
> > - if (!highest_pfn) {
> > + if (!highest_pfn && !kvm_para_available()) {
> > printk(KERN_WARNING "WARNING: strange, CPU MTRRs all
> > blank?\n");
> > WARN_ON(1);
> > - return 0;
> > }
> >
> > + if (!highest_pfn)
> > + return 0;
> > +
> > if (highest_pfn < end_pfn) {
> > printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't
> > cover"
> > " all of memory, losing %luMB of RAM.\n",
> > --
> > 1.5.3.7
> >
>
> Doest that WARN_ON(1) hurt?
Yes. It inidicates a problem where there isn't one. In a virtual machine
MTRRs make absolutly no sense and so they should all be blank there.
Joerg
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