From 0e9e09880d5f65ccb178d6c5785305ecf5715bba Mon Sep 17 00:00:00 2001 From: Elena Ufimtseva Date: Tue, 29 Sep 2015 13:53:31 +0200 Subject: [PATCH] PVH Dom0 RMRR IOMMU mapping regression fix This patch addresses a regression introduced by commit 5ae03990c120a7b3067a52d9784c9aa72c0705a6 in new set_identity_p2m_entry. RMRRs are not being mapped in IOMMU for PVH Dom0. This causes pages faults and some long 'hang-like' delays during Dom0 PVH boot and device assignments. During construct_dom0, in PVH path p2m is being constructed and identity mapped in IOMMU. The p2m type is p2m_mmio_direct and p2m access p2m_rwx. New code used to map RMRRs invoked from rmrr_identity_mapping checks if p2m entry exists with same type and access and if yes, skips iommu mapping. Since there are p2m entries for pvh dom0 iomem, RMRRs are not being mapped in IOMMU. As was mentioned in the earlier discussion, the PVH Dom0 construction code should be modified to properly map RMRR regions in IOMMU. Since change will be too invasive, this solution is a temporary fix at this time before better solution is in. Also as Jan mentioned, there is no need in having 'x' permissions for p2m entry of a mmio region, thus changed here. Signed-off-by: Elena Ufimtseva Reviewed-by: Jan Beulich --- xen/arch/x86/domain_build.c | 4 ++-- xen/arch/x86/mm/p2m.c | 9 +++++++++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c index cd27864a3d..c2ef87a01c 100644 --- a/xen/arch/x86/domain_build.c +++ b/xen/arch/x86/domain_build.c @@ -432,9 +432,9 @@ static __init void pvh_add_mem_mapping(struct domain *d, unsigned long gfn, } if ( rangeset_contains_singleton(mmio_ro_ranges, mfn + i) ) - a = p2m_access_rx; + a = p2m_access_r; else - a = p2m_access_rwx; + a = p2m_access_rw; if ( (rc = set_mmio_p2m_entry(d, gfn + i, _mfn(mfn + i), a)) ) panic("pvh_add_mem_mapping: gfn:%lx mfn:%lx i:%ld rc:%d\n", diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c index cf8485ed44..09144e0384 100644 --- a/xen/arch/x86/mm/p2m.c +++ b/xen/arch/x86/mm/p2m.c @@ -979,7 +979,16 @@ int set_identity_p2m_entry(struct domain *d, unsigned long gfn, ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K, p2m_mmio_direct, p2ma); else if ( mfn_x(mfn) == gfn && p2mt == p2m_mmio_direct && a == p2ma ) + { ret = 0; + /* + * PVH fixme: during Dom0 PVH construction, p2m entries are being set + * but iomem regions are not mapped with IOMMU. This makes sure that + * RMRRs are correctly mapped with IOMMU. + */ + if ( is_hardware_domain(d) && !iommu_use_hap_pt(d) ) + ret = iommu_map_page(d, gfn, gfn, IOMMUF_readable|IOMMUF_writable); + } else { if ( flag & XEN_DOMCTL_DEV_RDM_RELAXED ) -- 2.30.2