[PATCH] KVM: PCIPT: VT-d: Check if context mapping succeed or not

[PATCH] KVM: PCIPT: VT-d: Check if context mapping succeed or not

[Han, Weidong]

>From 3898ee02c07054af2867ed49cd7973016aab2132 Mon Sep 17 00:00:00 2001
From: Weidong Han <weidong.han@intel.com>
Date: Mon, 23 Jun 2008 16:45:56 +0800
Subject: [PATCH] Check if context mapping succeed or not

If context mapping fails, return error. And also, don't need to restore
back host linux iommu domain for detached device in
kvm_iommu_unmap_guest().

Signed-off-by: Weidong Han <weidong.han@intel.com>
---
 arch/x86/kvm/vtd.c |   18 +++++++-----------
 1 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/vtd.c b/arch/x86/kvm/vtd.c
index be775cd..7bbd353 100644
--- a/arch/x86/kvm/vtd.c
+++ b/arch/x86/kvm/vtd.c
@@ -104,12 +104,17 @@ found:
 		printk(KERN_ERR "kvm_iommu_map_guest: domain ==
NULL\n");
 	else
 		printk("kvm_iommu_map_guest: domain = %p\n",
kvm->arch.domain);
-		
+
 	if (kvm_iommu_map_memslots(kvm)) {
 		kvm_iommu_unmap_memslots(kvm);
 		return -EFAULT;
 	}
-	kvm_intel_iommu_context_mapping(kvm->arch.domain, pdev);
+
+	if (kvm_intel_iommu_context_mapping(kvm->arch.domain, pdev)) {
+		printk(KERN_ERR "Domain context map for %s failed",
+		       pci_name(pdev));
+		return -EFAULT;
+	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_iommu_map_guest);
@@ -153,7 +158,6 @@ static int kvm_iommu_unmap_memslots(struct kvm *kvm)
 
 int kvm_iommu_unmap_guest(struct kvm *kvm)
 {
-	struct dmar_domain *domain;
 	struct kvm_pci_pt_dev_list *entry;
 	struct pci_dev *pdev = NULL;
 
@@ -181,14 +185,6 @@ found:
 		/* detach kvm dmar domain */
 		kvm_intel_iommu_detach_dev(kvm->arch.domain,
 				pdev->bus->number, pdev->devfn);
-
-		/* now restore back linux iommu domain */
-		domain = kvm_intel_iommu_find_domain(pdev);
-		if (domain)
-			kvm_intel_iommu_context_mapping(domain, pdev);
-		else
-			printk(KERN_DEBUG
-				"kvm_iommu_unmap_guest: domain ==
NULL\n");
 	}
 	kvm_iommu_unmap_memslots(kvm);
 	kvm_intel_iommu_domain_exit(kvm->arch.domain);
-- 
1.5.1

Re: [PATCH] KVM: PCIPT: VT-d: Check if context mapping succeed or not

[Muli Ben-Yehuda]

Hi Weidong,

Minor comments below.

On Mon, Jun 23, 2008 at 10:53:17PM +0800, Han, Weidong wrote:


>  		printk("kvm_iommu_map_guest: domain = %p\n",
> kvm->arch.domain);
> -		
> +

This patch is line-wrapped, and there's some uneeded whitespace above.

>  	if (kvm_iommu_map_memslots(kvm)) {
>  		kvm_iommu_unmap_memslots(kvm);
>  		return -EFAULT;
>  	}
> -	kvm_intel_iommu_context_mapping(kvm->arch.domain, pdev);
> +
> +	if (kvm_intel_iommu_context_mapping(kvm->arch.domain, pdev)) {
> +		printk(KERN_ERR "Domain context map for %s failed",
> +		       pci_name(pdev));
> +		return -EFAULT;
> +	}

Why not return the return value from kvm_intel_iommu_context_mapping()
directly? It will make debugging a little bit easier.

Cheers,
Muli