From: Liang Li Date: Thu, 5 Feb 2015 12:59:48 +0000 (+0100) Subject: x86: avoid needless EPT table ajustment and cache flush X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~3784 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=06ed8cc2cc9be465719ac8f8def03a43e34064da;p=xen.git x86: avoid needless EPT table ajustment and cache flush When a guest change it's MTRR MSRs, ajusting EPT table and flushing cache are needed only when guest has IOMMU device, using need_iommu(d) can minimize the impact to guest with device assigned, since a guest may be hot plugged with a device thus there may be dirty cache lines before need_iommu(d) becoming true, force the p2m_memory_type_changed and flush_all when the first device is assigned to guest to amend this issue. Signed-off-by: Liang Li Signed-off-by: Yang Zhang Acked-by: Kevin Tian --- diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c index 76b3c2a660..a69ee62a65 100644 --- a/xen/arch/x86/hvm/mtrr.c +++ b/xen/arch/x86/hvm/mtrr.c @@ -789,7 +789,7 @@ HVM_REGISTER_SAVE_RESTORE(MTRR, hvm_save_mtrr_msr, hvm_load_mtrr_msr, void memory_type_changed(struct domain *d) { - if ( iommu_enabled && d->vcpu && d->vcpu[0] ) + if ( need_iommu(d) && d->vcpu && d->vcpu[0] ) { p2m_memory_type_changed(d); flush_all(FLUSH_CACHE); diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c index 78c6977d74..b93e7d8e71 100644 --- a/xen/drivers/passthrough/pci.c +++ b/xen/drivers/passthrough/pci.c @@ -1365,6 +1365,13 @@ static int assign_device(struct domain *d, u16 seg, u8 bus, u8 devfn) } } d->need_iommu = 1; + /* + * There may be dirty cache lines when a device is assigned + * and before need_iommu(d) becoming true, this will cause + * memory_type_changed lose effect if memory type changes. + * Call memory_type_changed here to amend this. + */ + memory_type_changed(d); } pdev = pci_get_pdev_by_domain(hardware_domain, seg, bus, devfn);