[Xen-changelog] [xen master] hvm/hpet: In hpet_save, call hpet_get_comparator.

[patchbot@xxxxxxx]

commit a206319856c6b59b606bb27f1ee896b5ff5a74e7
Author:     Don Slutz <dslutz@xxxxxxxxxxx>
AuthorDate: Fri May 2 16:18:04 2014 -0400
Commit:     Tim Deegan <tim@xxxxxxx>
CommitDate: Thu May 8 12:03:53 2014 +0100

    hvm/hpet: In hpet_save, call hpet_get_comparator.
    
    This changes save data to consistent/expected values.  It is not
    technically required because hpet_get_comparator() will adjust from
    any value to the correct value. And hpet_get_comparator() is
    effectivly called in hpet_load via hpet_set_timer.
    
    However it does look strange to people that the output from
    xen-hvmctx for the comparator values do not change when the master
    clock does.
    
    The software-developers-hpet-spec-1-0a.pdf says that the comparator
    will allways be greater than master clock for a periodic timer.
    
    Signed-off-by: Don Slutz <dslutz@xxxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Tim Deegan <tim@xxxxxxx>
---
 xen/arch/x86/hvm/hpet.c |   18 +++++++++++++++---
 1 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
index 0789947..b611304 100644
--- a/xen/arch/x86/hvm/hpet.c
+++ b/xen/arch/x86/hvm/hpet.c
@@ -495,12 +495,14 @@ static int hpet_save(struct domain *d, 
hvm_domain_context_t *h)
 {
     HPETState *hp = domain_vhpet(d);
     int rc;
+    uint64_t guest_time;
 
     spin_lock(&hp->lock);
+    guest_time = guest_time_hpet(hp);
 
     /* Write the proper value into the main counter */
     if ( hpet_enabled(hp) )
-        hp->hpet.mc64 = hp->mc_offset + guest_time_hpet(hp);
+        hp->hpet.mc64 = hp->mc_offset + guest_time;
 
     /* Save the HPET registers */
     rc = _hvm_init_entry(h, HVM_SAVE_CODE(HPET), 0, HVM_SAVE_LENGTH(HPET));
@@ -524,8 +526,18 @@ static int hpet_save(struct domain *d, 
hvm_domain_context_t *h)
         C(period[1]);
         C(period[2]);
 #undef C
-        /* save the 64 bit comparator in the 64 bit timer[n].cmp field
-         * regardless of whether or not the timer is in 32 bit mode. */
+        /*
+         * read the comparator to get it updated so hpet_save will
+         * return the expected value.
+         */
+        hpet_get_comparator(hp, 0, guest_time);
+        hpet_get_comparator(hp, 1, guest_time);
+        hpet_get_comparator(hp, 2, guest_time);
+        /*
+         * save the 64 bit comparator in the 64 bit timer[n].cmp
+         * field regardless of whether or not the timer is in 32 bit
+         * mode.
+         */
         rec->timers[0].cmp = hp->hpet.comparator64[0];
         rec->timers[1].cmp = hp->hpet.comparator64[1];
         rec->timers[2].cmp = hp->hpet.comparator64[2];
--
generated by git-patchbot for /home/xen/git/xen.git#master

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