From: George Dunlap <george.dunlap@citrix.com>
To: Sergey Dyasli <sergey.dyasli@citrix.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Kevin Tian <kevin.tian@intel.com>,
"jun.nakajima@intel.com" <jun.nakajima@intel.com>,
"jbeulich@suse.com" <jbeulich@suse.com>,
Andrew Cooper <Andrew.Cooper3@citrix.com>
Subject: Re: [PATCH 2/9] x86/np2m: Have invept flush all np2m entries with the same base pointer
Date: Mon, 2 Oct 2017 10:40:16 +0100 [thread overview]
Message-ID: <ece159a4-1c64-df25-0a08-ad1d02265ca9@citrix.com> (raw)
In-Reply-To: <1506937045.3729.1.camel@citrix.com>
On 10/02/2017 10:37 AM, Sergey Dyasli wrote:
> On Fri, 2017-09-29 at 16:01 +0100, George Dunlap wrote:
>> nvmx_handle_invept() updates current's np2m just to flush it. This is
>> not only wasteful, but ineffective: if several L2 vcpus share the same
>> np2m base pointer, they all need to be flushed (not only the current
>> one).
>
> I don't follow this completely. L1 will use INVEPT on each vCPU that
> shares the same np2m pointer. The main idea here was not to update
> current's np2m just to flush it.
Hmm, yes the INVEPT thing is true. But if that's the case, why do we
need np2m_flush_base() to loop over the whole list and flush all np2ms
with the same pointer?
-George
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next prev parent reply other threads:[~2017-10-02 9:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-29 15:01 [PATCH 1/9] x86/np2m: refactor p2m_get_nestedp2m() George Dunlap
2017-09-29 15:01 ` [PATCH 2/9] x86/np2m: Have invept flush all np2m entries with the same base pointer George Dunlap
2017-10-02 9:37 ` Sergey Dyasli
2017-10-02 9:40 ` George Dunlap [this message]
2017-10-02 10:07 ` George Dunlap
2017-10-02 10:24 ` Sergey Dyasli
2017-09-29 15:01 ` [PATCH 3/9] x86/np2m: remove np2m_base from p2m_get_nestedp2m() George Dunlap
2017-09-29 15:01 ` [PATCH 4/9] x86/np2m: Simplify nestedhvm_hap_nested_page_fault George Dunlap
2017-10-02 9:39 ` Sergey Dyasli
2017-09-29 15:01 ` [PATCH 5/9] x86/vvmx: Make updating shadow EPTP value more efficient George Dunlap
2017-09-29 15:56 ` Andrew Cooper
2017-10-02 9:41 ` Sergey Dyasli
2017-09-29 15:01 ` [PATCH 6/9] x86/np2m: Send flush IPIs only when a vcpu is actively using a shadow p2m George Dunlap
2017-09-29 15:01 ` [PATCH 7/9] x86/np2m: implement sharing of np2m between vCPUs George Dunlap
2017-09-29 15:01 ` [PATCH 8/9] x86/np2m: refactor p2m_get_nestedp2m_locked() George Dunlap
2017-09-29 15:01 ` [PATCH 9/9] x86/np2m: add break to np2m_flush_eptp() George Dunlap
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