[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1/2] x86/hvm: Always do SMAP check when updating runstate_guest(v)
>>> On 09.07.14 at 03:33, <feng.wu@xxxxxxxxx> wrote: >> From: Andrew Cooper [mailto:andrew.cooper3@xxxxxxxxxx] >> On 08/07/14 00:18, Feng Wu wrote: >> > In the current implementation, we honor the guest's CPL and AC >> > to determain whether do the SMAP check or not for runstate_guest(v). >> > However, this doesn't work. The VMCS feild is invalid when we try >> > to get geust's SS by hvm_get_segment_register(), since the >> > right VMCS has not beed loaded for the current VCPU. >> > >> > In this patch, we always do the SMAP check when updating >> > runstate_guest(v) for the guest when SMAP is enabled by it. >> > >> > Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx> >> > Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx> >> >> Why can't the VMCS be reloaded in vmx_ctxt_switch_to() rather than >> vmx_do_resume() ? The problem is not with updating the runstate area >> persay, but due to using guest_walk_tables() during a context switch >> before the VMCS has been loaded. > > This is another option in the discussion with Jan. However, seems > the current option is preferred by Jan. I don't think I ever said so. What I probably did say is that doing it the alternative way, while presumably better, will need quite a bit more care (i.e. is overall more risky than the change here). Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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