From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vitaly Kuznetsov Subject: [PATCH RFCv2 1/1] Introduce VCPUOP_reset_vcpu_info Date: Thu, 14 Aug 2014 10:28:02 +0200 Message-ID: <1408004882-7256-2-git-send-email-vkuznets@redhat.com> References: <1408004882-7256-1-git-send-email-vkuznets@redhat.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 1XHqON-0004Wa-47 for xen-devel@lists.xenproject.org; Thu, 14 Aug 2014 08:28:15 +0000 In-Reply-To: <1408004882-7256-1-git-send-email-vkuznets@redhat.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: xen-devel@lists.xenproject.org Cc: Andrew Jones , Stefano Stabellini , David Vrabel , Jan Beulich List-Id: xen-devel@lists.xenproject.org When an SMP guest performs kexec/kdump it tries issuing VCPUOP_register_vcpu_info. This fails due to vcpu_info already being registered. Introduce new vcpu operation to reset vcpu_info to its default state. Based on the original patch by Konrad Rzeszutek Wilk. Signed-off-by: Vitaly Kuznetsov --- Changes from RFCv1: - Don't use unsuitable unmap_vcpu_info(), rewrite [Jan Beulich] - Require FIFO ABI being in 2-level mode - Describe limitations in include/public/vcpu.h [Jan Beulich] --- xen/arch/x86/hvm/hvm.c | 1 + xen/common/domain.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++ xen/include/public/vcpu.h | 14 +++++++++++ 3 files changed, 76 insertions(+) diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 216c3f2..7917272 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -3332,6 +3332,7 @@ static long hvm_vcpu_op( case VCPUOP_set_singleshot_timer: case VCPUOP_stop_singleshot_timer: case VCPUOP_register_vcpu_info: + case VCPUOP_reset_vcpu_info: case VCPUOP_register_vcpu_time_memory_area: rc = do_vcpu_op(cmd, vcpuid, arg); break; diff --git a/xen/common/domain.c b/xen/common/domain.c index 44e5cbe..889c313 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -1116,6 +1116,67 @@ long do_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg) break; } + case VCPUOP_reset_vcpu_info: + { + vcpu_info_t *old_info; + unsigned int i; + + if ( !test_bit(_VPF_down, &v->pause_flags) ) + { + printk(XENLOG_G_WARNING + "%pv: VCPU is up, refusing to reset vcpu_info!\n", v); + return -EBUSY; + } + + if ( v->evtchn_fifo ) + { + printk(XENLOG_G_WARNING "%pv: FIFO evtchn ABI is being used," + "refusing to reset vcpu_info!\n", v); + return -EBUSY; + } + + if ( v->vcpu_info_mfn == INVALID_MFN ) + { + rc = 0; + break; + } + + domain_lock(d); + old_info = v->vcpu_info; + + if ( vcpuid < XEN_LEGACY_MAX_VCPUS ) + { + memcpy(&shared_info(d, vcpu_info[vcpuid]), v->vcpu_info, + sizeof(vcpu_info_t)); + v->vcpu_info = (vcpu_info_t *)&shared_info(d, vcpu_info[vcpuid]); + } + else + { + v->vcpu_info = &dummy_vcpu_info; + } + unmap_domain_page_global((void *) + ((unsigned long)old_info & PAGE_MASK)); + + put_page_and_type(mfn_to_page(v->vcpu_info_mfn)); + v->vcpu_info_mfn = INVALID_MFN; + + /* Make sure vcpu_info was set */ + smp_wmb(); + + if ( vcpuid < XEN_LEGACY_MAX_VCPUS ) + { + /* + * Mark everything as being pending to make sure nothing gets lost. + */ + vcpu_info(v, evtchn_upcall_pending) = 1; + for ( i = 0; i < BITS_PER_EVTCHN_WORD(d); i++ ) + set_bit(i, &vcpu_info(v, evtchn_pending_sel)); + } + domain_unlock(d); + rc = 0; + break; + } + case VCPUOP_register_runstate_memory_area: { struct vcpu_register_runstate_memory_area area; diff --git a/xen/include/public/vcpu.h b/xen/include/public/vcpu.h index e888daf..81bc1b9 100644 --- a/xen/include/public/vcpu.h +++ b/xen/include/public/vcpu.h @@ -227,6 +227,20 @@ struct vcpu_register_time_memory_area { typedef struct vcpu_register_time_memory_area vcpu_register_time_memory_area_t; DEFINE_XEN_GUEST_HANDLE(vcpu_register_time_memory_area_t); +/* + * Reset all of the vcpu_info information from their previous location + * to the default one used at bootup. The following prerequisites should be met: + * 1. VCPU should be switched off. This means the operation is unsupported for + * boot VCPU. + * 2. Domain should not be using FIFO-based event channel ABI. In case it is in + * use domain is supposed to switch back to 2-level ABI with EVTCHNOP_reset. + * + * After the call vcpu_info is reset to its default state: first + * XEN_LEGACY_MAX_VCPUS VCPUs will get it switched to shared_info and all other + * VCPUs will get dummy_vcpu_info. + */ +#define VCPUOP_reset_vcpu_info 14 + #endif /* __XEN_PUBLIC_VCPU_H__ */ /* -- 1.9.3