[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] [PATCH V2] x86/p2m: fixed p2m_change_type_range() start / end check
- To: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxx>
- From: George Dunlap <george.dunlap@xxxxxxxxxx>
- Date: Mon, 23 Apr 2018 15:28:53 +0100
- Autocrypt: addr=george.dunlap@xxxxxxxxxx; prefer-encrypt=mutual; keydata= xsFNBFPqG+MBEACwPYTQpHepyshcufo0dVmqxDo917iWPslB8lauFxVf4WZtGvQSsKStHJSj 92Qkxp4CH2DwudI8qpVbnWCXsZxodDWac9c3PordLwz5/XL41LevEoM3NWRm5TNgJ3ckPA+J K5OfSK04QtmwSHFP3G/SXDJpGs+oDJgASta2AOl9vPV+t3xG6xyfa2NMGn9wmEvvVMD44Z7R W3RhZPn/NEZ5gaJhIUMgTChGwwWDOX0YPY19vcy5fT4bTIxvoZsLOkLSGoZb/jHIzkAAznug Q7PPeZJ1kXpbW9EHHaUHiCD9C87dMyty0N3TmWfp0VvBCaw32yFtM9jUgB7UVneoZUMUKeHA fgIXhJ7I7JFmw3J0PjGLxCLHf2Q5JOD8jeEXpdxugqF7B/fWYYmyIgwKutiGZeoPhl9c/7RE Bf6f9Qv4AtQoJwtLw6+5pDXsTD5q/GwhPjt7ohF7aQZTMMHhZuS52/izKhDzIufl6uiqUBge 0lqG+/ViLKwCkxHDREuSUTtfjRc9/AoAt2V2HOfgKORSCjFC1eI0+8UMxlfdq2z1AAchinU0 eSkRpX2An3CPEjgGFmu2Je4a/R/Kd6nGU8AFaE8ta0oq5BSFDRYdcKchw4TSxetkG6iUtqOO ZFS7VAdF00eqFJNQpi6IUQryhnrOByw+zSobqlOPUO7XC5fjnwARAQABzSRHZW9yZ2UgVy4g RHVubGFwIDxkdW5sYXBnQHVtaWNoLmVkdT7CwYAEEwEKACoCGwMFCwkIBwMFFQoJCAsFFgID AQACHgECF4ACGQEFAlpk2IEFCQo9I54ACgkQpjY8MQWQtG1A1BAAnc0oX3+M/jyv4j/ESJTO U2JhuWUWV6NFuzU10pUmMqpgQtiVEVU2QbCvTcZS1U/S6bqAUoiWQreDMSSgGH3a3BmRNi8n HKtarJqyK81aERM2HrjYkC1ZlRYG+jS8oWzzQrCQiTwn3eFLJrHjqowTbwahoiMw/nJ+OrZO /VXLfNeaxA5GF6emwgbpshwaUtESQ/MC5hFAFmUBZKAxp9CXG2ZhTP6ROV4fwhpnHaz8z+BT NQz8YwA4gkmFJbDUA9I0Cm9D/EZscrCGMeaVvcyldbMhWS+aH8nbqv6brhgbJEQS22eKCZDD J/ng5ea25QnS0fqu3bMrH39tDqeh7rVnt8Yu/YgOwc3XmgzmAhIDyzSinYEWJ1FkOVpIbGl9 uR6seRsfJmUK84KCScjkBhMKTOixWgNEQ/zTcLUsfTh6KQdLTn083Q5aFxWOIal2hiy9UyqR VQydowXy4Xx58rqvZjuYzdGDdAUlZ+D2O3Jp28ez5SikA/ZaaoGI9S1VWvQsQdzNfD2D+xfL qfd9yv7gko9eTJzv5zFr2MedtRb/nCrMTnvLkwNX4abB5+19JGneeRU4jy7yDYAhUXcI/waS /hHioT9MOjMh+DoLCgeZJYaOcgQdORY/IclLiLq4yFnG+4Ocft8igp79dbYYHkAkmC9te/2x Kq9nEd0Hg288EO/OwE0EVFq6vQEIAO2idItaUEplEemV2Q9mBA8YmtgckdLmaE0uzdDWL9To 1PL+qdNe7tBXKOfkKI7v32fe0nB4aecRlQJOZMWQRQ0+KLyXdJyHkq9221sHzcxsdcGs7X3c 17ep9zASq+wIYqAdZvr7pN9a3nVHZ4W7bzezuNDAvn4EpOf/o0RsWNyDlT6KECs1DuzOdRqD oOMJfYmtx9hMzqBoTdr6U20/KgnC/dmWWcJAUZXaAFp+3NYRCkk7k939VaUpoY519CeLrymd Vdke66KCiWBQXMkgtMGvGk5gLQLy4H3KXvpXoDrYKgysy7jeOccxI8owoiOdtbfM8TTDyWPR Ygjzb9LApA8AEQEAAcLBZQQYAQoADwUCVFq6vQIbDAUJAeEzgAAKCRCmNjwxBZC0bWknD/97 Tkh3PMAcvMZINmJefBdYYspmwTWZSR9USsy68oWzDsXKNDNTqBC781lR/7PSqhqaSOmSnty3 FNblaBYKfMV3OOWgrP0H8Voqp4IgH3yOOkQLVITIwulqbbxQtmCsJ3xkhZm6CA0EKbc9VM/j FX3aCAfOJf52vlY1gXjYOvVjrdrRrBXEjs8E5f6EsrQKDrWCKNx/9qRfmtsQeKHTsgpINkpZ s11ClX/sM/RCR9/BgB/K08QQZYsWD6lgZh1KxLXRzKRunba0L+jpcRsoQFUMj/ofrfnHAdl0 q2upzISM/wR8aer+kekMo+y00schmYJYu5JAAzbjQQuhCAg0UTBGPaNwteL2l3c9Ps8on1nl mq9TnbYwGLAxJzXSb3BATgz7dygpsBBNS5WhUNQgIJvcZJbLggEIqjZGs8o7/+dt4klwxCYL FVlsWYSwEjX0UYHVLMS/F7FcXbCMUeoN/4krmRyv7YICE/VDQSDPcSKedzWvQM8T+5uY5pFJ NiIaa6asFndP50GiKbFtD6xAM+rbnwT7Io+iPtvD/3ddMXQs58IVMzgNA/hcdOX/qlx6Jqk/ hYQQsl4HoQsx/GyrNiwiPErTx32QNeXxoGYm6kwxt7F5qK7AN5tyYNkEyoxYrv8bl9VjAve8 hpECyf4O1mOGC/dIuBCDk8gxL5Pbo3jl98LBZQQYAQoADwIbDAUCVlNqsQUJA9njdAAKCRCm NjwxBZC0bbJMEACigmtpL2lzS47DXydApr1X8SYCHIPc39OjvmErjP05lKUZjmesmhlM5eKO gPb/fzeJ0wXB4J8OyseIJ0D/XwyLLQeM8d/HUFFMBWr+HE7jIukAUXeQ6GRwR+MBYGK/KmR9 JHbMAUz8f3G087Ma12BfpNWayndlFwR3rvdV4lvlyx6cl0EaFhbzPu/N07HG5MTk0evtphgZ 7wuG1oAtO+DGA6orHEicor6nBAQNZzPyjqo40dBxTs+amx7UndMRPSL1dD57eJwbbvBeNa8I w8wT7oNy2/C21VWmSy5XzMzcUTgmjmQz6DSNJPz2dMK4Y/LtcVFTfSZTmlBIkfoc9Vay2EB9 3z2EmjZwGT7n/DRu9QDtLbXyeVTBuLTaP3D+q5AyR1/5Z4T0LhwNvxeND5yO+YNAwqocZwL+ OcctpSZUBpAuU4Ju/9JKMX57GlnbjB8YGahoBJsQZx4CZyw0MXlkCk5cR0EPjY9iI2CEA5lO QueOSbo0hf1ZJwCx724lx0WSwL8ngd8wZTYMNc8GngaU61kmzfcuCklhokTxQdK7Efme5ccv A1txzgGewx9mDhPgNcJweasBnyL0N3wya2RMAzm04gCio8y4FKQepwQpKCNKAYZIU4juAPxn nb6cbBGiMGO1NDuxG+qvl1cMElnq+cuhSUlZdr2sE9JRfa0gucLBZQQYAQoADwIbDAUCWHQN VAUJBfqGFwAKCRCmNjwxBZC0bbgCD/oC6mWUrxQKWPDvFE9+fzm8UKqKP7aciz+gvWUN3o4i 4sRFNyvAEOW/QY2zwM1pN07BFZ3Z+8AVxpgR6h7RQzDJYSPZ5k5WWCJzJEQs2sPI5rfYJGK8 um7mlsSvf2xcLK/1Aj07BmWDjR6glDDRY+iMmSSdHe6Te6tiQPPS6Woj8AE3qf5lBsdvcEln nrkSwzNeVKRQQROUOskVw4WmCsNJjZtKmrVpgId3df/5HWG7Bi4nPwA8IFOt6O72lJlkORFy DF5P7ML7Pc5LbEFimzETPBxTJzVu1UoOQb/THB+qxhKMXXudSf/5sdMhwvOwItIcc5pib/v6 7gWK48bAzoOTgNYzmDCVC/roeLLU2SpEQIlIR0eAaWImgt8VEtre3Gch33e41DtbUli54DX0 dRdhqQaDM1T1q77VyDoZcs+SpGX9Ic9mxl+BN+6vtGIUVgaOG5pF85aQlRfCD6IlFQgiZtiR XeRpeIYG27RUw5kIljW+VxPMdBUvZpUXEazqjoPvBKybg0oKFfMXrMj4vHo6J0FD3ZEToGnP dANspUCZRewRozjp7ZWIu7QfGasfJNQ8c1IDiAFl3rV+dAGXXdmrDcX6w2q5lqoFz+8npK2I ehKCA94U+J/RLywUiaLuHnXt40WvQ98kHm7uTsy36iWqqawPqzmn8m5ruynVHmmcXsLBZQQY AQoADwIbDAUCWmTXMwUJB+tP9gAKCRCmNjwxBZC0bb+2D/9hjn1k5WcRHlu19WGuH6q0Kgm1 LRT7PnnSz904igHNElMB5a7wRjw5kdNwU3sRm2nnmHeOJH8kYj2Hn1QgX5SqQsysWTHWOEse GeoXydx9zZZkt3oQJM+9NV1VjK0bOXwqhiQyEUWz5/9l467FS/k4FJ5CHNRumvhLa0l2HEEu 5pxq463HQZHDt4YE/9Y74eXOnYCB4nrYxQD/GSXEZvWryEWreDoaFqzq1TKtzHhFgQG7yFUE epxLRUUtYsEpT6Rks2l4LCqG3hVD0URFIiTyuxJx3VC2Ta4LH3hxQtiaIpuXqq2D4z63h6vC x2wxfZc/WRHGbr4NAlB81l35Q/UHyMocVuYLj0llF0rwU4AjiKZ5qWNSEdvEpL43fTvZYxQh DCjQTKbb38omu5P4kOf1HT7s+kmQKRtiLBlqHzK17D4K/180ADw7a3gnmr5RumcZP3NGSSZA 6jP5vNqQpNu4gqrPFWNQKQcW8HBiYFgq6SoLQQWbRxJDHvTRYJ2ms7oCe870gh4D1wFFqTLe yXiVqjddENGNaP8ZlCDw6EU82N8Bn5LXKjR1GWo2UK3CjrkHpTt3YYZvrhS2MO2EYEcWjyu6 LALF/lS6z6LKeQZ+t9AdQUcILlrx9IxqXv6GvAoBLJY1jjGBq+/kRPrWXpoaQn7FXWGfMqU+ NkY9enyrlw==
- Cc: george.dunlap@xxxxxxxxxxxxx, andrew.cooper3@xxxxxxxxxx, jbeulich@xxxxxxxx
- Delivery-date: Mon, 23 Apr 2018 14:29:00 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Openpgp: preference=signencrypt
On 04/23/2018 12:56 PM, Razvan Cojocaru wrote:
> On 04/23/2018 02:47 PM, George Dunlap wrote:
>> On 04/18/2018 02:12 PM, Razvan Cojocaru wrote:
>>> p2m_change_type_range() handles end > max_mapped_pfn, but not
>>> start > max_mapped_pfn. Check the latter just after grabbing the
>>> lock and bail if true.
>>>
>>> Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
>>> Suggested-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>>
>> Sorry, I meant to reply to this earlier but I haven't been able to make
>> the time.
>>
>> On reflection, I think this is the wrong approach actually. First, my
>> assertion was incorrect: the p2m_altp2m_propagate_change() is gated on
>> p2m->max_remapped_gfn, not max_mapped_gfn (nb the 're'). So setting
>> max_mapped_gfn shouldn't cause 'unnecessary' propagations.
>>
>> Secondly, we do actually need to keep the logdirty ranges of all the
>> p2ms in sync, even if they're past the max_remapped_gfn. Otherwise we
>> could have the following situation:
>> * altp2m created, max_remapped_gfn 0x1000
>> * screen resized, logdirty range [0x2000-0x3000]; change dropped
>> * guest accesses 0x4000, max_remapped_gfn set to 0x4000
>> * change_p2m_type happens, and the 0x2000-0x3000 range is not marked
>> logrdirty #
>>
>> So while it would be an improvement to make the assertion more explicit,
>> I don't (anymore) think it would actually be an improvement to discard
>> changes that are above max_mapped_gfn. (And thus your original patch,
>> which copied max_mapped_gfn into the altp2ms, was probably closer to the
>> right approach).
>>
>> Sorry for the confusion -- we obviously need a bit more thought about
>> how altp2m and logdirty interact.
>
> Thanks for the reply! Fair enough.
>
> FWIW, the attached patch works well for me, resizes and all (but it
> could very well be just luck).
I think we really want some sort of analysis of all the ways the two
features might interact, and some justification as to why a solution is
complete.
You're not aiming to get a patch like this into 4.11 though, are you?
-George
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
