[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH 1/4] x86/PVH: de-duplicate mappings for first Mb of Dom0 memory
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
- Date: Tue, 31 Aug 2021 14:27:50 +0100
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.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; bh=Ia1kB0C85GHc1LlulK+3kx3ilzfPvMweUNMVqRuPZ9w=; b=c5+JkuRYcbEvfniyDhTBwreQ4eIZ0tqxVrtYqlBOZM3zFnA5XYVJKLT/lg1Axs4KodcZOeWea8iSAHPhVndcqWfGKVNnoMQLXSOzl6fY4JeGpuAXBeBcXZHHdXCgwM+ezSjcnaF1Mp2f7w/8JAOUAEBStI1/aGPZNIklM3acK9bw4/G5s8KRd0oL5K2Qm6BnHiwafVtipYiVxSm05S5YeaIVrRbGDgemzt/4PoN062+ZXbB5mTuqYFu36Y+wLNdZwi1PuhFvgHZwwApO8IjxmvD3pKzuKhQ3oudlesFwqI3MHmf2ikO4BuFLDOgz8fit8dSPe2t6cOi089Qd8kR7hA==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=PvSrDu75WliPtqyh2g3GAmDJx3HTqLu90ZmoKBDZdjpaugV9mGykOQLJpusCv2U1KD/SB4jIKKC5xLtDmYNQe6z9qSYwcF99nBBU+709Gfh8mXY8TBJpgzPpjmuY5cbdGBjurvUyUihIMmOFzVjLKIhdbqki6xJwrN6QQfETPtRk514wWeUxOodpiBwrUL8j5vAknhR3+fdEK+4T/9KnIiBmUEGaXVWl/n8wIgLbZ+7VZAU4u+fDjX/oBQb9cYtcWvF29TDzR/Clc00iQn1jhEytH/LerrdU2+q2ir2zPzulqjdljP6kwDcYBGTv0xvdaOhSGL7EW7N80dng5HWx/A==
- Authentication-results: esa3.hc3370-68.iphmx.com; dkim=pass (signature verified) header.i=@citrix.onmicrosoft.com
- Cc: Wei Liu <wl@xxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- Delivery-date: Tue, 31 Aug 2021 13:28:03 +0000
- Ironport-hdrordr: A9a23:z3tvuqr5+Qto7gtgs0kUAZoaV5ulL9V00zEX/kB9WHVpm5Oj+P xGzc526farslsssREb+OxpOMG7MBbhHO1OkPYs1NCZLXXbUQqTXfxfBO7ZrQEIdBeOjtK1uZ 0QFJSWTeeAd2SS7vyKkDVQcexQueVvmZrA7Yy1rwYPPHNXguNbnmNE426gYzxLrWJ9dPwE/f Snl6h6TnabCA8qhpPRPAh6YwGPnayFqLvWJTo9QzI34giHij2lrJb8Dhijxx8bFxdC260r/2 TpmxHwovzLiYD79jbsk0voq7hGktrozdVOQOSKl8guMz3pziKlfp5oVbGutC085Muv9FEput /RpApIBbU811rhOkWO5Tf90Qjp1zgjr1fk1F+jmHPm5ff0QTorYvAxz75xQ1/80Q4Nrdt82K VE0yayrJxMFy7Nmyz7+pzhSwxqvlDcmwthrccjy1hkFacOYr5YqoISuGlPFo0bIS784Ic7VM FzEcDn4upMe1/yVQGbgoBW+q3pYp0PJGbAfqBb0fbllQS+3UoJj3fw/fZv20vpr/kGOsB5D4 2uCNUaqFlMJvVmJp6VSt1xGfdepwT2MGTx2VmpUCDa/Zc8SjrwQq7MkcAIDd6RCes1JbsJ6d n8uQBjxCIPk3yHM7zG4HQMyGGXfFmA
- Ironport-sdr: MwIa6lkkHwHt+hBFLgabAp+wWEZowpD1gk3/IynmNbXKg5e/KhRkarV4yR9AgkpHouCOgdasiM LEigp60vft4pyG1GF47e4332nwe74Wn6NEx+6+v76G5uxpFfAsM4lPct6n4RWbpqR95pg1CJMj cP0WoeagQEHHIjStoA50Dckr8bcxB+DlTr+A1Rx4ufm4VUfAHsZp8FTqkfAbcSF3IQnxTC/hR6 Y/fuBrRjOU4SuGIBDFajUufsgKo26XVxhhU0/F9kpxNK5eUsK74wstNK9KV2tIUrq3ncbsn9de r6F8TF+p6vHLturd9c3/68XQ
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 31/08/2021 14:19, Jan Beulich wrote:
>>>> @@ -1095,6 +1101,17 @@ static int __init pvh_setup_acpi(struct
>>>> nr_pages = PFN_UP((d->arch.e820[i].addr & ~PAGE_MASK) +
>>>> d->arch.e820[i].size);
>>>>
>>>> + /* Memory below 1MB has been dealt with by pvh_populate_p2m(). */
>>>> + if ( pfn < PFN_DOWN(MB(1)) )
>>>> + {
>>>> + if ( pfn + nr_pages <= PFN_DOWN(MB(1)) )
>>>> + continue;
>>>> +
>>>> + /* This shouldn't happen, but is easy to deal with. */
>>> I'm not sure this comment is helpful.
>>>
>>> Under PVH, there is nothing special about the 1M boundary, and we can
>>> reasonably have something else here or crossing the boundary.
>> As long as we have this special treatment of the low Mb, the boundary
>> is meaningful imo. I'd see the comment go away when the handling in
>> general gets streamlined.
> I should have added: And as long as Dom0's E820 map gets cloned from
> the host's, which will necessarily consider the 1Mb boundary special.
Not when you're booting virtualised in the first place.
~Andrew
|
