From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCHv2 2/4] Implement bare minimum of HYPER-V MSRs. Date: Sun, 17 Jan 2010 14:44:34 +0200 Message-ID: <20100117124433.GD31692@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:20777 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973Ab0AQMog (ORCPT ); Sun, 17 Jan 2010 07:44:36 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o0HCiZre026592 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Sun, 17 Jan 2010 07:44:36 -0500 Content-Disposition: inline In-Reply-To: <4B52FE45.60405@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 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? > >+ 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. > >+ kvm_x86_ops->patch_hypercall(vcpu, (unsigned char *)addr); > >+ ((unsigned char *)addr)[3] = 0xc3; /* ret */ > > kvm_write_guest(), this can fault. > > >+int kvm_hv_hypercall(struct kvm_vcpu *vcpu) > >+{ > >+ u64 param, ingpa, outgpa, ret; > >+ uint16_t code, rep_idx, rep_cnt, res = HV_STATUS_SUCCESS, rep_done = 0; > >+ bool fast, longmode; > >+ int cs_db, cs_l; > >+ > >+ /* > >+ * hypercall generates UD from non zero cpl and real mode > >+ * per HYPER-V spec > >+ */ > >+ if (kvm_x86_ops->get_cpl(vcpu) != 0 || !(vcpu->arch.cr0& X86_CR0_PE)) { > > Use kvm_read_cr0_bits() to avoid caching. > > > -- > error compiling committee.c: too many arguments to function -- Gleb.