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Re: [Qemu-devel] [PATCH 1/3] target-i386: kvm: Abort if MCE bank count i
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH 1/3] target-i386: kvm: Abort if MCE bank count is not supported by host |
Date: |
Wed, 25 Nov 2015 15:26:17 -0200 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Wed, Nov 25, 2015 at 05:46:38PM +0100, Paolo Bonzini wrote:
>
>
> On 25/11/2015 16:49, Eduardo Habkost wrote:
> > Instead of silently changing the number of banks in mcg_cap based
> > on kvm_get_mce_cap_supported(), abort initialization if the host
> > doesn't support MCE_BANKS_DEF banks.
> >
> > Note that MCE_BANKS_DEF was always 10 since it was introduced in
> > QEMU, and Linux always returned 32 at KVM_CAP_MCE since
> > KVM_CAP_MCE was introduced, so no behavior is being changed and
> > the error can't be triggered by any Linux version. The point of
> > the new check is to ensure we won't silently change the bank
> > count if we change MCE_BANKS_DEF or make the bank count
> > configurable in the future.
> >
> > Signed-off-by: Eduardo Habkost <address@hidden>
> > ---
> > target-i386/kvm.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> > index 2a9953b..ee7bc69 100644
> > --- a/target-i386/kvm.c
> > +++ b/target-i386/kvm.c
> > @@ -784,11 +784,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
> > return ret;
> > }
> >
> > - if (banks > MCE_BANKS_DEF) {
> > - banks = MCE_BANKS_DEF;
> > + if (MCE_BANKS_DEF > banks) {
> > + error_report("kvm: Unsupported MCE bank count: %d > %d\n",
> > + MCE_BANKS_DEF, banks);
>
> Yoda conditions?
>
> if (banks < MCE_BANKS_DEF) {
> error_report("kvm: Unsupported MCE bank count (QEMU = %d, KVM =
> %d)",
> MCE_BANKS_DEF, banks);
This was on purpose, because MCE_BANKS_DEF is replaced by
(env->mcg_caps & MCG_CAPS_COUNT_MASK) in the next patch.
--
Eduardo