[Xen-changelog] Several page allocations, done in the hypervisor when starting an HVM

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID d714f923b7cfff705dcf9aae30a06709340059aa
# Parent  f4f2ff82e7977f2dcd4ed6312451d04113569c2b
Several page allocations, done in the hypervisor when starting an HVM
domain, are not checked.  This can cause the physical machine to crash
when starting the HVM domain during low-memory conditions.

Kudos to Charles Arnold for catching the problem with
shadow_direct_map_init.

Signed-off-by: Charles Coffing <ccoffing@xxxxxxxxxx>
---
 xen/arch/x86/hvm/hvm.c      |    6 +++++-
 xen/arch/x86/hvm/svm/svm.c  |    4 +++-
 xen/arch/x86/hvm/svm/vmcb.c |   17 ++++++++++-------
 3 files changed, 18 insertions(+), 9 deletions(-)

diff -r f4f2ff82e797 -r d714f923b7cf xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Fri May 19 16:08:51 2006 +0100
+++ b/xen/arch/x86/hvm/hvm.c    Fri May 19 16:10:52 2006 +0100
@@ -189,7 +189,11 @@ void hvm_setup_platform(struct domain* d
     if ( !hvm_guest(current) || (current->vcpu_id != 0) )
         return;
 
-    shadow_direct_map_init(d);
+    if ( shadow_direct_map_init(d) == 0 )
+    {
+        printk("Can not allocate shadow direct map for HVM domain.\n");
+        domain_crash_synchronous();
+    }
 
     hvm_map_io_shared_page(d);
     hvm_get_info(d);
diff -r f4f2ff82e797 -r d714f923b7cf xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c        Fri May 19 16:08:51 2006 +0100
+++ b/xen/arch/x86/hvm/svm/svm.c        Fri May 19 16:10:52 2006 +0100
@@ -458,6 +458,9 @@ int start_svm(void)
     
     if (!(test_bit(X86_FEATURE_SVME, &boot_cpu_data.x86_capability)))
         return 0;
+    svm_globals[cpu].hsa = alloc_host_save_area();
+    if (! svm_globals[cpu].hsa)
+        return 0;
     
     rdmsr(MSR_EFER, eax, edx);
     eax |= EFER_SVME;
@@ -466,7 +469,6 @@ int start_svm(void)
     printk("AMD SVM Extension is enabled for cpu %d.\n", cpu );
 
     /* Initialize the HSA for this core */
-    svm_globals[cpu].hsa = alloc_host_save_area();
     phys_hsa = (u64) virt_to_maddr( svm_globals[cpu].hsa ); 
     phys_hsa_lo = (u32) phys_hsa;
     phys_hsa_hi = (u32) (phys_hsa >> 32);    
diff -r f4f2ff82e797 -r d714f923b7cf xen/arch/x86/hvm/svm/vmcb.c
--- a/xen/arch/x86/hvm/svm/vmcb.c       Fri May 19 16:08:51 2006 +0100
+++ b/xen/arch/x86/hvm/svm/vmcb.c       Fri May 19 16:10:52 2006 +0100
@@ -139,17 +139,20 @@ static int construct_vmcb_controls(struc
 
     /* The following is for I/O and MSR permision map */
     iopm = alloc_xenheap_pages(get_order_from_bytes(IOPM_SIZE));
-
-    ASSERT(iopm);
-    memset(iopm, 0xff, IOPM_SIZE);
-    clear_bit(PC_DEBUG_PORT, iopm);
+    if (iopm)
+    {
+        memset(iopm, 0xff, IOPM_SIZE);
+        clear_bit(PC_DEBUG_PORT, iopm);
+    }
     msrpm = alloc_xenheap_pages(get_order_from_bytes(MSRPM_SIZE));
-
-    ASSERT(msrpm);
-    memset(msrpm, 0xff, MSRPM_SIZE);
+    if (msrpm)
+        memset(msrpm, 0xff, MSRPM_SIZE);
 
     arch_svm->iopm = iopm;
     arch_svm->msrpm = msrpm;
+
+    if (! iopm || ! msrpm)
+        return 1;
 
     vmcb->iopm_base_pa = (u64) virt_to_maddr(iopm);
     vmcb->msrpm_base_pa = (u64) virt_to_maddr(msrpm);

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