[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v6 05/18] tools/libxc: support to resume uncooperative HVM guests
On 01/26/2016 02:21 AM, Konrad Rzeszutek Wilk wrote: > On Wed, Dec 30, 2015 at 10:28:55AM +0800, Wen Congyang wrote: >> Befor this patch: > > s/Befor/Before >> 1. suspend >> a. PVHVM and PV: we use the same way to suspend the guest (send the suspend >> request to the guest). If the guest doesn't support evtchn, the xenstore >> variant will be used, suspending the guest via XenBus control node. >> b. pure HVM: we call xc_domain_shutdown(..., SHUTDOWN_suspend) to suspend >> the guest >> >> 2. Resume: >> a. fast path > > s/fast path/fast path(fast=1) > >> In this case, we don't change the guest's state. And we will call >> libxl__domain_resume(..., 1) to resume the guest. > > Do not change the guest state. We call libxl__domain_resume(.., 1) which > calls xc_domain_resume(..., 1 /* fast=1*/) to resume the guest. > > >> PV: modify the return code to 1, and than call the domctl > > s/domctl/domctl:/ >> XEN_DOMCTL_resumedomain >> PVHVM: same with PV >> pure HVM: do nothing in modify_returncode, and than call the domctl: >> XEN_DOMCTL_resumedomain > >> b. slow >> Used when the guest's state have been changed. And we will call > > s/And we will/Will/ > >> libxl__domain_resume(..., 0) to resume the guest. >> PV: update start info, and reset all secondary CPU states. Than call >> the domctl: XEN_DOMCTL_resumedomain >> PVHVM: can not be resumed. You will get the following error message: >> "Cannot resume uncooperative HVM guests" >> purt HVM: same with PVHVM >> >> After this patch: >> 1. suspend >> unchanged >> >> 2. Resume >> a. fast path: >> unchanged >> b. slow >> PV: unchanged >> PVHVM: call XEN_DOMCTL_resumedomain to resume the guest. Because we >> don't modify the return code, the PV driver will disconnect >> and reconnect. I am not sure if we should update start info >> and reset all secondary CPU states. > > The guest ends up doing the XENMAPSPACE_shared_info XENMEM_add_to_physmap > hypercall and resetting all of its CPU states to point to the shared_info > (well except the ones past 32). > > That is the Linux kernel does that - regardless whether the > SCHEDOP_shutdown:SHUTDOWN_suspend returns 1 or not. Yes, I find it in the Linux kernel. Thanks for pointing it out. > >> Pure HVM: call XEN_DOMCTL_resumedomain to resume the guest. >> >> Under COLO, we will update the guest's state(modify memory, cpu's registers, >> device status...). In this case, we cannot use the fast path to resume it. >> Keep the return code 0, and use a slow path to resume the guest. While >> resuming HVM using slow path is not supported currently, this patch is to >> make the resume call do not fail. > > s/do/to/ >> >> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx> >> Signed-off-by: Yang Hongyang <hongyang.yang@xxxxxxxxxxxx> >> --- >> tools/libxc/xc_resume.c | 24 ++++++++++++++++++++---- >> 1 file changed, 20 insertions(+), 4 deletions(-) >> >> diff --git a/tools/libxc/xc_resume.c b/tools/libxc/xc_resume.c >> index 87d4324..503e4f8 100644 >> --- a/tools/libxc/xc_resume.c >> +++ b/tools/libxc/xc_resume.c >> @@ -108,6 +108,25 @@ static int xc_domain_resume_cooperative(xc_interface >> *xch, uint32_t domid) >> return do_domctl(xch, &domctl); >> } >> >> +static int xc_domain_resume_hvm(xc_interface *xch, uint32_t domid) >> +{ >> + DECLARE_DOMCTL; >> + >> + /* >> + * This domctl XEN_DOMCTL_resumedomain just unpause each vcpu. After > > s/This/The/ > s/just// >> + * this domctl, the guest will run. > s/this/the/ > >> + * >> + * If it is PVHVM, the guest called the hypercall HYPERVISOR_sched_op > > s/HYPERVISOR_sched_op/SCHEDOP_shutdown:SHUTDOWN_suspend/ >> + * to suspend itself. We don't modify the return code, so the PV driver >> + * will disconnect and reconnect. >> + * >> + * If it is a HVM, the guest will continue running. >> + */ >> + domctl.cmd = XEN_DOMCTL_resumedomain; >> + domctl.domain = domid; >> + return do_domctl(xch, &domctl); >> +} >> + >> static int xc_domain_resume_any(xc_interface *xch, uint32_t domid) >> { >> DECLARE_DOMCTL; >> @@ -137,10 +156,7 @@ static int xc_domain_resume_any(xc_interface *xch, >> uint32_t domid) >> */ >> #if defined(__i386__) || defined(__x86_64__) >> if ( info.hvm ) >> - { >> - ERROR("Cannot resume uncooperative HVM guests"); >> - return rc; >> - } >> + return xc_domain_resume_hvm(xch, domid); >> >> if ( xc_domain_get_guest_width(xch, domid, &dinfo->guest_width) != 0 ) >> { >> -- >> 2.5.0 >> >> >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@xxxxxxxxxxxxx >> http://lists.xen.org/xen-devel > > > . > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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