Messages in this thread | | | Date | Fri, 13 Apr 2012 18:05:29 +0800 | From | Xiao Guangrong <> | Subject | [PATCH v2 00/16] KVM: MMU: fast page fault |
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Thanks for Avi and Marcelo's review, i have simplified the whole things in this version: - it only fix the page fault with PFEC.P = 1 && PFEC.W = 0 that means unlock set_spte path can be dropped.
- it only fixes the page fault caused by dirty-log
In this version, all the information we need is from spte, the SPTE_ALLOW_WRITE bit and SPTE_WRITE_PROTECT bit: - SPTE_ALLOW_WRITE is set if the gpte is writable and the pfn pointed by the spte is writable on host. - SPTE_WRITE_PROTECT is set if the spte is write-protected by shadow page table protection.
All these bits can be protected by cmpxchg, now, all the things is fairly simple than before. :)
Performance test:
autotest migration: (Host: Intel(R) Xeon(R) CPU X5690 @ 3.47GHz * 12 + 32G)
- For ept:
Before: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 104 214 323 2 68 238 310 3 68 242 314
After: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 101 190 295 2 67 188 259 3 66 217 289
- For shadow mmu:
Before: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 103 235 342 2 64 219 286 3 68 234 305
After: smp2.Fedora.16.64.migrate Times .unix .with_autotest.dbench.unix total 1 104 220 328 2 65 204 273 3 64 219 286
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