[Xen-changelog] [xen master] x86/vvmx: Fix handing of the MSR_BITMAP field with VMCS shadowing

[patchbot@xxxxxxx]

commit 930f7879248edc05d9cb812e692eee6eb3b70eac
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Jul 19 10:28:03 2017 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Jul 27 11:39:57 2017 +0100

    x86/vvmx: Fix handing of the MSR_BITMAP field with VMCS shadowing
    
    Currently, the following sequence of actions:
    
     * VMPTRLD (creates a mapping, likely pointing at gfn 0 for an empty vmcs)
     * VMWRITE CPU_BASED_VM_EXEC_CONTROL (completed by hardware)
     * VMWRITE MSR_BITMAP (completed by hardware)
     * VMLAUNCH
    
    results in an L2 guest running with ACTIVATE_MSR_BITMAP set, but Xen using a
    stale mapping (likely gfn 0) when reading the interception bitmap.  The
    MSR_BITMAP field needs unconditionally intercepting even with VMCS 
shadowing,
    so Xen's mapping of the bitmap can be updated.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vvmx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 0d08789..f84478e 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -98,13 +98,15 @@ int nvmx_vcpu_initialise(struct vcpu *v)
         clear_page(vw);
 
         /*
-         * For the following 4 encodings, we need to handle them in VMM.
+         * For the following 6 encodings, we need to handle them in VMM.
          * Let them vmexit as usual.
          */
         set_bit(IO_BITMAP_A, vw);
         set_bit(VMCS_HIGH(IO_BITMAP_A), vw);
         set_bit(IO_BITMAP_B, vw);
         set_bit(VMCS_HIGH(IO_BITMAP_B), vw);
+        set_bit(MSR_BITMAP, vw);
+        set_bit(VMCS_HIGH(MSR_BITMAP), vw);
 
         unmap_domain_page(vw);
     }
--
generated by git-patchbot for /home/xen/git/xen.git#master

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxx
https://lists.xenproject.org/xen-changelog