[Xen-changelog] [xen stable-4.7] x86/hvm: do not register hpet mmio during s3 cycle

[patchbot@xxxxxxx]

commit a8d5690cc3d9b6f16ca4ff608c4d39adf39dd64e
Author:     Eric Chanudet <chanudete@xxxxxxxxxxxx>
AuthorDate: Thu Nov 16 12:01:28 2017 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Nov 16 12:01:28 2017 +0100

    x86/hvm: do not register hpet mmio during s3 cycle
    
    Do it once at domain creation (hpet_init).
    
    Sleep -> Resume cycles will end up crashing an HVM guest with hpet as
    the sequence during resume takes the path:
    -> hvm_s3_suspend
      -> hpet_reset
        -> hpet_deinit
        -> hpet_init
          -> register_mmio_handler
            -> hvm_next_io_handler
    
    register_mmio_handler will use a new io handler each time, until
    eventually it reaches NR_IO_HANDLERS, then hvm_next_io_handler calls
    domain_crash.
    
    Signed-off-by: Eric Chanudet <chanudete@xxxxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    master commit: 015d6738ddff4074668c1d4887bbffd507ed1a7f
    master date: 2017-11-14 17:09:50 +0100
---
 xen/arch/x86/hvm/hpet.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
index 3ea895a..f7aed7f 100644
--- a/xen/arch/x86/hvm/hpet.c
+++ b/xen/arch/x86/hvm/hpet.c
@@ -635,14 +635,10 @@ static int hpet_load(struct domain *d, 
hvm_domain_context_t *h)
 
 HVM_REGISTER_SAVE_RESTORE(HPET, hpet_save, hpet_load, 1, HVMSR_PER_DOM);
 
-void hpet_init(struct domain *d)
+static void hpet_set(HPETState *h)
 {
-    HPETState *h = domain_vhpet(d);
     int i;
 
-    if ( !has_vhpet(d) )
-        return;
-
     memset(h, 0, sizeof(HPETState));
 
     rwlock_init(&h->lock);
@@ -668,7 +664,14 @@ void hpet_init(struct domain *d)
         h->hpet.comparator64[i] = ~0ULL;
         h->pt[i].source = PTSRC_isa;
     }
+}
+
+void hpet_init(struct domain *d)
+{
+    if ( !has_vhpet(d) )
+        return;
 
+    hpet_set(domain_vhpet(d));
     register_mmio_handler(d, &hpet_mmio_ops);
     d->arch.hvm_domain.params[HVM_PARAM_HPET_ENABLED] = 1;
 }
@@ -697,8 +700,11 @@ void hpet_deinit(struct domain *d)
 
 void hpet_reset(struct domain *d)
 {
+    if ( !has_vhpet(d) )
+        return;
+
     hpet_deinit(d);
-    hpet_init(d);
+    hpet_set(domain_vhpet(d));
 }
 
 /*
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.7

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