From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCHv2 2/4] Implement bare minimum of HYPER-V MSRs. Date: Sun, 17 Jan 2010 14:49:30 +0200 Message-ID: <4B53075A.4020209@redhat.com> References: <1263719028-24765-1-git-send-email-gleb@redhat.com> <1263719028-24765-3-git-send-email-gleb@redhat.com> <4B52FE45.60405@redhat.com> <20100117124433.GD31692@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:4169 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751371Ab0AQMtc (ORCPT ); Sun, 17 Jan 2010 07:49:32 -0500 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o0HCnVVW002039 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 17 Jan 2010 07:49:32 -0500 In-Reply-To: <20100117124433.GD31692@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 01/17/2010 02:44 PM, Gleb Natapov wrote: > On Sun, Jan 17, 2010 at 02:10:45PM +0200, Avi Kivity wrote: > >> On 01/17/2010 11:03 AM, Gleb Natapov wrote: >> >>> Minimum HYPER-V implementation should have GUEST_OS_ID, HYPERCALL and >>> VP_INDEX MSRs. >>> >>> >>> TRACE_EVENT(kvm_pio, >>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >>> index 4d835b6..db0b2b1 100644 >>> --- a/arch/x86/kvm/x86.c >>> +++ b/arch/x86/kvm/x86.c >>> @@ -630,7 +630,8 @@ static u32 msrs_to_save[] = { >>> #ifdef CONFIG_X86_64 >>> MSR_CSTAR, MSR_KERNEL_GS_BASE, MSR_SYSCALL_MASK, MSR_LSTAR, >>> #endif >>> - MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA >>> + MSR_IA32_TSC, MSR_IA32_PERF_STATUS, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA, >>> + HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL, >>> }; >>> >> These will be disabled since the msrs don't exist on the host. See >> the comment above and KVM_SAVE_MSRS_BEGIN. >> >> > I see. Why not have two arrays? > Clearly better. >>> + case HV_X64_MSR_HYPERCALL: { >>> + u64 gfn; >>> + unsigned long addr; >>> + /* if guest os id is not set hypercall should remain disabled */ >>> + if (!kvm->arch.hv_guest_os_id&& data) >>> + break; >>> + kvm->arch.hv_hypercall = data; >>> + if (!kvm_hv_hypercall_enabled(kvm)) >>> + break; >>> + gfn = kvm->arch.hv_hypercall>> >>> + HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT; >>> + addr = gfn_to_hva(kvm, gfn); >>> + if (kvm_is_error_hva(addr)) >>> + return 1; >>> >> Should di the error check before assigning, perhaps. >> >> > Spec doesn't tell. And guest will get #GP and BSOD anyway. > Well, all msrs I know of either #GP, or store the value and do what they're supposed to do, never both. -- error compiling committee.c: too many arguments to function