From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [XEN PATCH 1/2] hvm: Support more than 32 VCPUS when migrating. Date: Tue, 22 Apr 2014 14:34:43 -0400 Message-ID: <20140422183443.GA6817__44790.3284956284$1398191808$gmane$org@phenom.dumpdata.com> References: <1396859560.22845.4.camel@kazak.uk.xensource.com> <1396977950-8789-1-git-send-email-konrad@kernel.org> <1396977950-8789-2-git-send-email-konrad@kernel.org> <534529A40200007800007055@nat28.tlf.novell.com> <20140409152706.GF5860@phenom.dumpdata.com> <5345853502000078000074F8@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WcfX1-0000d7-Co for xen-devel@lists.xenproject.org; Tue, 22 Apr 2014 18:34:59 +0000 Content-Disposition: inline In-Reply-To: <5345853502000078000074F8@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: keir@xen.org, linux-kernel@vger.kernel.org, konrad@kernel.org, david.vrabel@Citrix.com, xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com List-Id: xen-devel@lists.xenproject.org On Wed, Apr 09, 2014 at 04:36:53PM +0100, Jan Beulich wrote: > >>> On 09.04.14 at 17:27, wrote: > > On Wed, Apr 09, 2014 at 10:06:12AM +0100, Jan Beulich wrote: > >> >>> On 08.04.14 at 19:25, wrote: > >> > --- a/xen/arch/x86/hvm/hvm.c > >> > +++ b/xen/arch/x86/hvm/hvm.c > >> > @@ -3470,6 +3470,9 @@ static long hvm_vcpu_op( > >> > case VCPUOP_stop_singleshot_timer: > >> > case VCPUOP_register_vcpu_info: > >> > case VCPUOP_register_vcpu_time_memory_area: > >> > + case VCPUOP_down: > >> > + case VCPUOP_up: > >> > + case VCPUOP_is_up: > >> > >> This, if I checked it properly, leaves only VCPUOP_initialise, > >> VCPUOP_send_nmi, and VCPUOP_get_physid disallowed for HVM. > >> None of which look inherently bad to be used by HVM (but > >> VCPUOP_initialise certainly would need closer checking), so I > >> wonder whether either the wrapper shouldn't be dropped altogether > >> or at least be converted from a white list approach to a black list one. > > > > I was being conservative here because I did not want to allow the > > other ones without at least testing it. > > > > Perhaps that can be done as a seperate patch and this just as > > a bug-fix? > > I'm clearly not in favor of the patch as is - minimally I'd want it to > convert the white list to a black list. And once you do this it would > seem rather natural to not pointlessly add entries. With this patch: diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index b5b92fe..5eee790 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -3455,34 +3455,6 @@ static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg) } } -static long hvm_vcpu_op( - int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg) -{ - long rc; - - switch ( cmd ) - { - case VCPUOP_register_runstate_memory_area: - case VCPUOP_get_runstate_info: - case VCPUOP_set_periodic_timer: - case VCPUOP_stop_periodic_timer: - case VCPUOP_set_singleshot_timer: - case VCPUOP_stop_singleshot_timer: - case VCPUOP_register_vcpu_info: - case VCPUOP_register_vcpu_time_memory_area: - case VCPUOP_down: - case VCPUOP_up: - case VCPUOP_is_up: - rc = do_vcpu_op(cmd, vcpuid, arg); - break; - default: - rc = -ENOSYS; - break; - } - - return rc; -} - typedef unsigned long hvm_hypercall_t( unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long); @@ -3517,30 +3489,6 @@ static long hvm_memory_op_compat32(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg) return compat_memory_op(cmd, arg); } -static long hvm_vcpu_op_compat32( - int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg) -{ - long rc; - - switch ( cmd ) - { - case VCPUOP_register_runstate_memory_area: - case VCPUOP_get_runstate_info: - case VCPUOP_set_periodic_timer: - case VCPUOP_stop_periodic_timer: - case VCPUOP_set_singleshot_timer: - case VCPUOP_stop_singleshot_timer: - case VCPUOP_register_vcpu_info: - case VCPUOP_register_vcpu_time_memory_area: - rc = compat_vcpu_op(cmd, vcpuid, arg); - break; - default: - rc = -ENOSYS; - break; - } - - return rc; -} static long hvm_physdev_op_compat32( int cmd, XEN_GUEST_HANDLE_PARAM(void) arg) @@ -3563,7 +3511,7 @@ static long hvm_physdev_op_compat32( static hvm_hypercall_t *const hvm_hypercall64_table[NR_hypercalls] = { [ __HYPERVISOR_memory_op ] = (hvm_hypercall_t *)hvm_memory_op, [ __HYPERVISOR_grant_table_op ] = (hvm_hypercall_t *)hvm_grant_table_op, - [ __HYPERVISOR_vcpu_op ] = (hvm_hypercall_t *)hvm_vcpu_op, + HYPERCALL(vcpu_op), [ __HYPERVISOR_physdev_op ] = (hvm_hypercall_t *)hvm_physdev_op, HYPERCALL(xen_version), HYPERCALL(console_io), @@ -3583,7 +3531,7 @@ static hvm_hypercall_t *const hvm_hypercall64_table[NR_hypercalls] = { static hvm_hypercall_t *const hvm_hypercall32_table[NR_hypercalls] = { [ __HYPERVISOR_memory_op ] = (hvm_hypercall_t *)hvm_memory_op_compat32, [ __HYPERVISOR_grant_table_op ] = (hvm_hypercall_t *)hvm_grant_table_op_compat32, - [ __HYPERVISOR_vcpu_op ] = (hvm_hypercall_t *)hvm_vcpu_op_compat32, + COMPAT_CALL(vcpu_op), [ __HYPERVISOR_physdev_op ] = (hvm_hypercall_t *)hvm_physdev_op_compat32, COMPAT_CALL(xen_version), HYPERCALL(console_io), And with an HVM guest poking at the rest of VCPUOPs: VCPUOP_get_physid, VCPUOP_initialise, and VCPUOP_send_nmi - either before the CPU is up or when it is up - work. That is: the VCPUOP_get_physid would return -EINVAL; VCPUOP_initialise would return either -EEXIST or 0, and in either case the content of the ctxt was full of zeros. The VCPUOP_send_nmi did cause the HVM to get an NMI and it spitted out 'Dazed and confused'. It also noticed corruption: [ 3.611742] Corrupted low memory at c000fffc (fffc phys) = 00029b00 [ 2.386785] Corrupted low memory at ffff88000000fff8 (fff8 phys) = 2990000000000 Which is odd because there does not seem to be anything in the path of hypervisor that would cause this. > > Jan >