From: Razvan Cojocaru <rcojocaru@bitdefender.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: jun.nakajima@intel.com, kevin.tian@intel.com,
wei.liu2@citrix.com, ian.campbell@citrix.com,
stefano.stabellini@eu.citrix.com, george.dunlap@eu.citrix.com,
andrew.cooper3@citrix.com, ian.jackson@eu.citrix.com,
xen-devel@lists.xen.org, eddie.dong@intel.com,
Aravind.Gopalakrishnan@amd.com, suravee.suthikulpanit@amd.com,
tlengyel@novetta.com, keir@xen.org, boris.ostrovsky@oracle.com
Subject: Re: [PATCH V5 3/3] xen/vm_event: Deny register writes if refused by vm_event reply
Date: Tue, 14 Jul 2015 17:37:33 +0300 [thread overview]
Message-ID: <55A51EAD.7090000@bitdefender.com> (raw)
In-Reply-To: <55A51E1D0200007800090AF4@mail.emea.novell.com>
On 07/14/2015 03:35 PM, Jan Beulich wrote:
>> --- a/xen/include/public/vm_event.h
>> +++ b/xen/include/public/vm_event.h
>> @@ -74,6 +74,11 @@
>> * VM_EVENT_FLAG_SET_EMUL_READ_DATA are set, only the latter will be honored).
>> */
>> #define VM_EVENT_FLAG_SET_EMUL_READ_DATA (1 << 5)
>> + /*
>> + * Deny completion of the operation that triggered the event.
>> + * Currently only useful for MSR, CR0, CR3 and CR4 write events.
>> + */
>> +#define VM_EVENT_FLAG_DENY (1 << 6)
>
> Wouldn't this want adding to the get-capabilities sub-op too?
Actually, no (sorry for rushing with the answer before), the monitor.c
capabilities issue refers to main event types, whereas this is a
response flag.
45 static inline uint32_t get_capabilities(struct domain *d)
46 {
47 uint32_t capabilities = 0;
48
49 /*
50 * At the moment only Intel HVM domains are supported. However,
event
51 * delivery could be extended to AMD and PV domains.
52 */
53 if ( !is_hvm_domain(d) || !cpu_has_vmx )
54 return capabilities;
55
56 capabilities = (1 << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG) |
57 (1 << XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR) |
58 (1 << XEN_DOMCTL_MONITOR_EVENT_SOFTWARE_BREAKPOINT) |
59 (1 << XEN_DOMCTL_MONITOR_EVENT_GUEST_REQUEST);
60
61 /* Since we know this is on VMX, we can just call the hvm func */
62 if ( hvm_is_singlestep_supported() )
63 capabilities |= (1 << XEN_DOMCTL_MONITOR_EVENT_SINGLESTEP);
64
65 return capabilities;
66 }
So if we have the (1 << XEN_DOMCTL_MONITOR_EVENT_WRITE_CTRLREG) and (1
<< XEN_DOMCTL_MONITOR_EVENT_MOV_TO_MSR), that also means we can deny
those writes (by setting the VM_EVENT_FLAG_DENY in the vm_event
response), no additional checks are necessary.
Thanks,
Razvan
next prev parent reply other threads:[~2015-07-14 14:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-13 17:14 [PATCH V5 0/3] Vm_event memory introspection helpers Razvan Cojocaru
2015-07-13 17:14 ` [PATCH V5 1/3] xen/mem_access: Support for memory-content hiding Razvan Cojocaru
2015-07-13 17:32 ` Lengyel, Tamas
2015-07-13 17:36 ` Razvan Cojocaru
2015-07-14 12:22 ` Jan Beulich
2015-07-14 13:26 ` Razvan Cojocaru
2015-07-14 13:37 ` Jan Beulich
2015-07-14 13:41 ` Razvan Cojocaru
2015-07-13 17:14 ` [PATCH V5 2/3] xen/vm_event: Support for guest-requested events Razvan Cojocaru
2015-07-13 17:14 ` [PATCH V5 3/3] xen/vm_event: Deny register writes if refused by vm_event reply Razvan Cojocaru
2015-07-14 12:35 ` Jan Beulich
2015-07-14 13:45 ` Razvan Cojocaru
2015-07-14 14:41 ` Jan Beulich
2015-07-14 15:04 ` Razvan Cojocaru
2015-07-14 15:55 ` Jan Beulich
2015-07-14 16:25 ` Razvan Cojocaru
2015-07-14 14:37 ` Razvan Cojocaru [this message]
2015-07-14 10:50 ` [PATCH V5 0/3] Vm_event memory introspection helpers Jan Beulich
2015-07-14 11:45 ` Razvan Cojocaru
2015-07-14 11:53 ` Jan Beulich
2015-07-14 13:08 ` Ian Campbell
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