From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "Xu, Pengfei" <pengfei.xu@intel.com>,
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"Yu, Yu-cheng" <yu-cheng.yu@intel.com>,
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Cc: "kirill.shutemov@linux.intel.com" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v29 09/32] x86/mm: Introduce _PAGE_COW
Date: Sat, 21 Aug 2021 19:20:32 +0000 [thread overview]
Message-ID: <152f757d37d3fd834a06fadad18165cbf44b1b48.camel@intel.com> (raw)
In-Reply-To: <20210820181201.31490-10-yu-cheng.yu@intel.com>
+KVM list.
On Fri, 2021-08-20 at 11:11 -0700, Yu-cheng Yu wrote:
>
> static inline int pte_write(pte_t pte)
> {
> - return pte_flags(pte) & _PAGE_RW;
> + /*
> + * Shadow stack pages are always writable - but not by normal
> + * instructions, and only by shadow stack operations.
> Therefore,
> + * the W=0,D=1 test with pte_shstk().
> + */
> + return (pte_flags(pte) & _PAGE_RW) || pte_shstk(pte);
> }
>
KVM uses this in a couple places when checking EPT ptes. But bit 6
(dirty) is a totally different meaning in EPT. I think it's just used
to trigger an optimization, but wondering if KVM should have its own
TDP specific function instead of using pte_write().
next prev parent reply other threads:[~2021-08-21 19:20 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 18:11 [PATCH v29 00/32] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 01/32] Documentation/x86: Add CET description Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 02/32] x86/cet/shstk: Add Kconfig option for Shadow Stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 03/32] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 04/32] x86/cpufeatures: Introduce CPU setup and option parsing for CET Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 05/32] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 06/32] x86/cet: Add control-protection fault handler Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 07/32] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 08/32] x86/mm: Move pmd_write(), pud_write() up in the file Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 09/32] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2021-08-21 19:20 ` Edgecombe, Rick P [this message]
2021-08-22 2:59 ` Edgecombe, Rick P
2021-08-20 18:11 ` [PATCH v29 10/32] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 11/32] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 12/32] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY to _PAGE_COW Yu-cheng Yu
2021-08-26 10:42 ` Borislav Petkov
2021-08-20 18:11 ` [PATCH v29 13/32] mm: Move VM_UFFD_MINOR_BIT from 37 to 38 Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 14/32] mm: Introduce VM_SHADOW_STACK for shadow stack memory Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 15/32] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2021-08-26 10:55 ` Borislav Petkov
2021-08-20 18:11 ` [PATCH v29 16/32] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 17/32] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 18/32] mm: Add guard pages around a shadow stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 19/32] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 20/32] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 21/32] mm/mprotect: Exclude shadow stack from preserve_write Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 22/32] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 23/32] x86/cet/shstk: Add user-mode shadow stack support Yu-cheng Yu
2021-08-26 16:25 ` Borislav Petkov
2021-08-27 18:10 ` Yu, Yu-cheng
2021-08-27 18:21 ` Borislav Petkov
2021-08-27 18:37 ` Yu, Yu-cheng
2021-08-27 18:46 ` Borislav Petkov
2021-08-27 20:25 ` Dave Hansen
2021-09-01 13:00 ` Borislav Petkov
2021-09-01 15:24 ` Dave Hansen
2021-08-20 18:11 ` [PATCH v29 24/32] x86/process: Change copy_thread() argument 'arg' to 'stack_size' Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 25/32] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2021-08-26 16:50 ` Borislav Petkov
2021-08-26 17:22 ` H.J. Lu
2021-08-26 17:28 ` Borislav Petkov
2021-08-26 17:33 ` Yu, Yu-cheng
2021-08-26 17:25 ` Yu, Yu-cheng
2021-08-20 18:11 ` [PATCH v29 26/32] x86/cet/shstk: Introduce shadow stack token setup/verify routines Yu-cheng Yu
2021-08-26 17:21 ` Borislav Petkov
2021-08-20 18:11 ` [PATCH v29 27/32] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 28/32] ELF: Introduce arch_setup_elf_property() Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 29/32] x86/cet/shstk: Add arch_prctl functions for shadow stack Yu-cheng Yu
2021-08-20 18:11 ` [PATCH v29 30/32] mm: Move arch_calc_vm_prot_bits() to arch/x86/include/asm/mman.h Yu-cheng Yu
2021-08-20 18:12 ` [PATCH v29 31/32] mm: Update arch_validate_flags() to test vma anonymous Yu-cheng Yu
2021-08-20 18:12 ` [PATCH v29 32/32] mm: Introduce PROT_SHADOW_STACK for shadow stack Yu-cheng Yu
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