[Xen-changelog] [xen master] VMX: use non-atomic bitops to manage MSR state

[patchbot@xxxxxxx]

commit 3528b5b4c3b1695ecc7af5622b32042aafbdf6f4
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Jun 23 17:46:55 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jun 23 17:46:55 2016 +0200

    VMX: use non-atomic bitops to manage MSR state
    
    All host_msr_state accesses are solely on the owning CPU, and all
    guest_msr_state ones solely when the vCPU is current or being switched
    to. This, btw, is also in line with the use of find_first_set_bit()
    (which would be bogus if ->flags could get updated behind its back).
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 4edf283..65ee89e 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -339,9 +339,9 @@ void vmx_save_host_msrs(void)
 
 #define WRITE_MSR(address) do {                                         \
         guest_msr_state->msrs[VMX_INDEX_MSR_ ## address] = msr_content; \
-        set_bit(VMX_INDEX_MSR_ ## address, &guest_msr_state->flags);    \
+        __set_bit(VMX_INDEX_MSR_ ## address, &guest_msr_state->flags);  \
         wrmsrl(MSR_ ## address, msr_content);                           \
-        set_bit(VMX_INDEX_MSR_ ## address, &host_msr_state->flags);     \
+        __set_bit(VMX_INDEX_MSR_ ## address, &host_msr_state->flags);   \
     } while ( 0 )
 
 static enum handler_return
@@ -462,7 +462,7 @@ static void vmx_restore_host_msrs(void)
     {
         i = find_first_set_bit(host_msr_state->flags);
         wrmsrl(msr_index[i], host_msr_state->msrs[i]);
-        clear_bit(i, &host_msr_state->flags);
+        __clear_bit(i, &host_msr_state->flags);
     }
 }
 
@@ -495,9 +495,9 @@ static void vmx_restore_guest_msrs(struct vcpu *v)
         HVM_DBG_LOG(DBG_LEVEL_2,
                     "restore guest's index %d msr %x with value %lx",
                     i, msr_index[i], guest_msr_state->msrs[i]);
-        set_bit(i, &host_msr_state->flags);
+        __set_bit(i, &host_msr_state->flags);
         wrmsrl(msr_index[i], guest_msr_state->msrs[i]);
-        clear_bit(i, &guest_flags);
+        __clear_bit(i, &guest_flags);
     }
 
     if ( (v->arch.hvm_vcpu.guest_efer ^ read_efer()) & EFER_SCE )
--
generated by git-patchbot for /home/xen/git/xen.git#master

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