Binbin Wu a94b2a533e hv: ept: disable execute right on large pages ... Issue description: ----------------- Machine Check Error on Page Size Change Instruction fetch may cause machine check error if page size and memory type was changed without invalidation on some processors[1][2]. Malicious guest kernel could trigger this issue. This issue applies to both primary page table and extended page tables (EPT), however the primary page table is controlled by hypervisor only. This patch mitigates the situation in EPT. Mitigation details: ------------------ Implement non-execute huge pages in EPT. This patch series clears the execute permission (bit 2) in the EPT entries for large pages. When EPT violation is triggered by guest instruction fetch, hypervisor converts the large page to smaller 4 KB pages and restore the execute permission, and then re-execute the guest instruction. The current patch turns on the mitigation by default. The follow-up patches will conditionally turn on/off the feature per processor model. [1] Refer to erratum KBL002 in "7th Generation Intel Processor Family and 8th Generation Intel Processor Family for U Quad Core Platforms Specification Update" https://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/7th-gen-core-family-spec-update.pdf [2] Refer to erratum SKL002 in "6th Generation Intel Processor Family Specification Update" https://www.intel.com/content/www/us/en/products/docs/processors/core/desktop-6th-gen-core-family-spec-update.html Tracked-On: #4120 Signed-off-by: Binbin Wu <binbin.wu@intel.com> Reviewed-by: Eddie Dong <eddie.dong@intel.com>		2019-11-19 09:06:21 +08:00
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x86	hv: ept: disable execute right on large pages	2019-11-19 09:06:21 +08:00