[Xen-changelog] [xen stable-4.4] xen/arm: dump guest stack even if not the current VCPU

[patchbot@xxxxxxx]

commit 7bb6b2722be1e27f99948e5c68f7f42eb23f8e53
Author:     Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>
AuthorDate: Thu Oct 23 17:18:52 2014 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed Dec 10 14:09:35 2014 +0000

    xen/arm: dump guest stack even if not the current VCPU
    
    If show_guest_stack was called from Xen context (for instance hitting
    '0' key on Xen console) get_page_from_gva was not able to get the
    page returning NULL.
    Detecting different domain and changing VTTBR register make
    get_page_from_gva works for different domains.
    
    Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    (cherry picked from commit 281c892e3bdb0a56cfd8ab6516cd1a33c095c857)
---
 xen/arch/arm/p2m.c   |   24 ++++++++++++++++++++----
 xen/arch/arm/traps.c |    2 +-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index bc81b67..aff7a2c 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -688,13 +688,29 @@ struct page_info *get_page_from_gva(struct domain *d, 
vaddr_t va,
 {
     struct p2m_domain *p2m = &d->arch.p2m;
     struct page_info *page = NULL;
-    paddr_t maddr;
-
-    ASSERT(d == current->domain);
+    paddr_t maddr = 0;
+    int rc;
 
     spin_lock(&p2m->lock);
 
-    if ( gvirt_to_maddr(va, &maddr, flags) )
+    if ( unlikely(d != current->domain) )
+    {
+        unsigned long irq_flags;
+
+        local_irq_save(irq_flags);
+        p2m_load_VTTBR(d);
+
+        rc = gvirt_to_maddr(va, &maddr, flags);
+
+        p2m_load_VTTBR(current->domain);
+        local_irq_restore(irq_flags);
+    }
+    else
+    {
+        rc = gvirt_to_maddr(va, &maddr, flags);
+    }
+
+    if ( rc )
         goto err;
 
     if ( !mfn_valid(maddr >> PAGE_SHIFT) )
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 4c910c8..d527409 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -888,7 +888,7 @@ static void show_guest_stack(struct vcpu *v, struct 
cpu_user_regs *regs)
         return;
     }
 
-    page = get_page_from_gva(current->domain, sp, GV2M_READ);
+    page = get_page_from_gva(v->domain, sp, GV2M_READ);
     if ( page == NULL )
     {
         printk("Failed to convert stack to physical address\n");
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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