From db24f7f0123c3103e0d7860a7dc3be84463d1814 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Tue, 10 Jun 2014 16:58:47 +0200 Subject: [PATCH] libxc: use an explicit check for PV MSRs in xc_domain_save() Migrating PV domains using MSRs is not supported. This uses the new XEN_DOMCTL_get_vcpu_msrs and will fail the migration with an explicit error. This is an improvement upon the current failure of "No extended context for VCPUxx (ENOBUFS)" Support for migrating PV domains which are using MSRs will be included in the migration v2 work. Signed-off-by: Andrew Cooper Acked-by: Ian Campbell --- tools/libxc/xc_domain_save.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/tools/libxc/xc_domain_save.c b/tools/libxc/xc_domain_save.c index acf36854f5..778cbdef39 100644 --- a/tools/libxc/xc_domain_save.c +++ b/tools/libxc/xc_domain_save.c @@ -1995,6 +1995,26 @@ int xc_domain_save(xc_interface *xch, int io_fd, uint32_t dom, uint32_t max_iter goto out; } + /* Check there are no PV MSRs in use. */ + domctl.cmd = XEN_DOMCTL_get_vcpu_msrs; + domctl.domain = dom; + memset(&domctl.u, 0, sizeof(domctl.u)); + domctl.u.vcpu_msrs.vcpu = i; + domctl.u.vcpu_msrs.msr_count = 0; + set_xen_guest_handle_raw(domctl.u.vcpu_msrs.msrs, (void*)1); + + if ( xc_domctl(xch, &domctl) < 0 ) + { + if ( errno == ENOBUFS ) + { + errno = EOPNOTSUPP; + PERROR("Unable to migrate PV guest using MSRs (yet)"); + } + else + PERROR("Error querying maximum number of MSRs for VCPU%d", i); + goto out; + } + /* Start to fetch CPU eXtended States */ /* Get buffer size first */ domctl.cmd = XEN_DOMCTL_getvcpuextstate; -- 2.30.2