From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51839) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cmFvC-0005E0-HN for qemu-devel@nongnu.org; Fri, 10 Mar 2017 03:29:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cmFv7-00045q-FM for qemu-devel@nongnu.org; Fri, 10 Mar 2017 03:29:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33858) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cmFv7-00045m-A8 for qemu-devel@nongnu.org; Fri, 10 Mar 2017 03:29:05 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5C75DC0092A2 for ; Fri, 10 Mar 2017 08:29:05 +0000 (UTC) References: <20170309194634.28457-1-ehabkost@redhat.com> <20170309200759.GP2480@work-vm> <20170309202620.GZ4694@thinpad.lan.raisama.net> From: Paolo Bonzini Message-ID: <1528b8be-a766-9167-568e-dfd68527119c@redhat.com> Date: Fri, 10 Mar 2017 09:29:02 +0100 MIME-Version: 1.0 In-Reply-To: <20170309202620.GZ4694@thinpad.lan.raisama.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.9? v2] kvm: Print MSR information if KVM_{GET, SET}_MSRS failed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost , "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org On 09/03/2017 21:26, Eduardo Habkost wrote: > On Thu, Mar 09, 2017 at 08:08:00PM +0000, Dr. David Alan Gilbert wrote: >> * Eduardo Habkost (ehabkost@redhat.com) wrote: >>> When a KVM_{GET,SET}_MSRS ioctl() fails, it is difficult to find >>> out which MSR caused the problem. Print an error message for >>> debugging, before we trigger the (ret == cpu->kvm_msr_buf->nmsrs) >>> assert. >>> >>> Suggested-by: Dr. David Alan Gilbert >>> Signed-off-by: Eduardo Habkost >> >> Thanks! >> >> Reviewed-by: Dr. David Alan Gilbert >> >> I'd actually suggest it for 2.9; it's only added debug output. > > I think I agree. The patch is reasonably safe because we would be > already hitting the assert() if (ret < cpu->kvm_msr_buf->nmsrs) > anyway. > > Paolo, do you want to queue it for 2.9? Yes, with pleasure. Paolo >> >> Dave >> >>> --- >>> Changes v1 -> v2: >>> * Print error message on KVM_GET_MSRS too >>> * Suggested-by: Dr. David Alan Gilbert >>> --- >>> target/i386/kvm.c | 12 ++++++++++++ >>> 1 file changed, 12 insertions(+) >>> >>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c >>> index 887a81268f..705e971a63 100644 >>> --- a/target/i386/kvm.c >>> +++ b/target/i386/kvm.c >>> @@ -1807,6 +1807,12 @@ static int kvm_put_msrs(X86CPU *cpu, int level) >>> return ret; >>> } >>> >>> + if (ret < cpu->kvm_msr_buf->nmsrs) { >>> + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret]; >>> + error_report("error: failed to set MSR 0x%" PRIx32 " to 0x%" PRIx64, >>> + (uint32_t)e->index, (uint64_t)e->data); >>> + } >>> + >>> assert(ret == cpu->kvm_msr_buf->nmsrs); >>> return 0; >>> } >>> @@ -2172,6 +2178,12 @@ static int kvm_get_msrs(X86CPU *cpu) >>> return ret; >>> } >>> >>> + if (ret < cpu->kvm_msr_buf->nmsrs) { >>> + struct kvm_msr_entry *e = &cpu->kvm_msr_buf->entries[ret]; >>> + error_report("error: failed to get MSR 0x%" PRIx32, >>> + (uint32_t)e->index); >>> + } >>> + >>> assert(ret == cpu->kvm_msr_buf->nmsrs); >>> /* >>> * MTRR masks: Each mask consists of 5 parts >>> -- >>> 2.11.0.259.g40922b1 >>> >> -- >> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >