[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [PATCH] x86/EPT: squash meaningless TLB flush
- To: "Beulich, Jan" <JBeulich@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
- Date: Fri, 24 Dec 2021 07:45:04 +0000
- Accept-language: en-US
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=j0OXZXnuQ69lr+yVsU4srU4fkQHx2hKe1jbgwHdYyh8=; b=anEpK9YTmGDVHOrQgl0wXvQd3npM3jbPT17vvwuzB89TkrfD14vsjWQKn1dp/voL09fjIublUvuIS5/sbBk4FxxjhrmSK6DTh1ls2PjwyrkfBslm2cgNSlrYX70jV7c+lJAB+1nrMVyP71GpiyZw0UOQH0DTbvki4TuPgFRuGe6UxTeiITfmsmps7k7g6ScZp2wLMEtuPiLtxPBj0BkY4WhpKEupGTcL2PIXu4Nfe+l3KuyJrEEaO5xB2YuhseLuabSk1NEDphSdKhYo3GR4MDwaltny1dVm9IyXa7ehdjE+k0C+FVmeQrsj+JYy25Fu27qlrWeMJ9iruSjL7ubTQg==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=GI4hzGYHgSLVjwXnb0T+AWMXYQrr0ATgzryTm3P/KPN0VODKqJUCeCcLaaT8nILHGRXugp/mfq1aAoDxygCU5nJcoFeGicoA4IyI8p6P2j7NwHz+lFy0hMvCUtcwl9aBj6lWO1K5X7pjzBP+VuMZFmVopvBPhp0hXZWxaiKtRPB7IPClPKglTFv5XBZkRnW4AAGgOSrnad9yxaonbFnj6cjtPhiLjHgET+WKro0Bx4ppq50YwxnH0xlGMkUgeqX/kws69kOqUSt+udGW1Zca8X6vSpXEQvaVclgnGWVbdT3tVVPPzEpf6aFxKBan5sjAJjFxK0xndOIKnci9Widapg==
- Authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com;
- Cc: "Nakajima, Jun" <jun.nakajima@xxxxxxxxx>
- Delivery-date: Fri, 24 Dec 2021 07:45:13 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Thread-index: AQHX5gUNjzdaZ7T5YkaXVYM1ZhmrS6xBaC8w
- Thread-topic: [PATCH] x86/EPT: squash meaningless TLB flush
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: Wednesday, December 1, 2021 12:11 AM
>
> ept_free_entry() gets called after a flush - if one is necessary in the
> first place - was already issued. That behavior is similar to NPT, which
> also doesn't have any further flush in p2m_free_entry(). (Furthermore,
> the function being recursive, in case of recursiveness way too many
> flushes would have been issued.)
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
>
> --- a/xen/arch/x86/mm/p2m-ept.c
> +++ b/xen/arch/x86/mm/p2m-ept.c
> @@ -246,8 +246,7 @@ static void ept_free_entry(struct p2m_do
> ept_free_entry(p2m, epte + i, level - 1);
> unmap_domain_page(epte);
> }
> -
> - p2m_tlb_flush_sync(p2m);
> +
> p2m_free_ptp(p2m, mfn_to_page(_mfn(ept_entry->mfn)));
> }
>
|
