From: Roger Pau Monne Date: Thu, 11 Jan 2018 11:41:20 +0000 (+0000) Subject: xen/pvshim: use default position for the m2p mappings X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=b5be9c817d04b006886a0d7b87eacf7bd78f504d;p=people%2Fiwj%2Fxen.git xen/pvshim: use default position for the m2p mappings When running a 32bit kernel as Dom0 on a 64bit hypervisor the hypervisor will try to shrink the hypervisor hole to the minimum needed, and thus requires the Dom0 to use XENMEM_machphys_mapping in order to fetch the position of the start of the hypervisor virtual mappings. Disable this feature when running as a PV shim, since some DomU kernels don't implemented XENMEM_machphys_mapping and break if the m2p doesn't begin at the default address. NB: support for the XENMEM_machphys_mapping was added in Linux by commit 7e7750. Signed-off-by: Roger Pau Monné Acked-by: Jan Beulich --- diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c index 72752b8656..ebcb47bf26 100644 --- a/xen/arch/x86/pv/dom0_build.c +++ b/xen/arch/x86/pv/dom0_build.c @@ -398,7 +398,8 @@ int __init dom0_construct_pv(struct domain *d, if ( parms.pae == XEN_PAE_EXTCR3 ) set_bit(VMASST_TYPE_pae_extended_cr3, &d->vm_assist); - if ( (parms.virt_hv_start_low != UNSET_ADDR) && elf_32bit(&elf) ) + if ( !pv_shim && (parms.virt_hv_start_low != UNSET_ADDR) && + elf_32bit(&elf) ) { unsigned long mask = (1UL << L2_PAGETABLE_SHIFT) - 1; value = (parms.virt_hv_start_low + mask) & ~mask;