[Xen-devel] [V2 PATCH 0/9] x86/hvm: pkeys, add memory protection-key support

[Huaitong Han <huaitong.han@xxxxxxxxx>]

Changes in v2:
*Rebase all patches in staging branch
*Disable X86_CR4_PKE on hypervisor, and delete pkru_read/write functions, and
use xsave state read to get pkru value.
*Delete the patch that adds pkeys support for do_page_fault.
*Add pkeys support for gva2gfn so that setting _PAGE_PK_BIT in the return
value can get propagated to the guest correctly.

The protection-key feature provides an additional mechanism by which IA-32e
paging controls access to usermode addresses.

Hardware support for protection keys for user pages is enumerated with CPUID
feature flag CPUID.7.0.ECX[3]:PKU. Software support is CPUID.7.0.ECX[4]:OSPKE
with the setting of CR4.PKE(bit 22).

When CR4.PKE = 1, every linear address is associated with the 4-bit protection
key located in bits 62:59 of the paging-structure entry that mapped the page
containing the linear address. The PKRU register determines, for each
protection key, whether user-mode addresses with that protection key may be
read or written.

The PKRU register (protection key rights for user pages) is a 32-bit register
with the following format: for each i (0 â i â 15), PKRU[2i] is the
access-disable bit for protection key i (ADi); PKRU[2i+1] is the write-disable
bit for protection key i (WDi).

Software can use the RDPKRU and WRPKRU instructions with ECX = 0 to read and
write PKRU. In addition, the PKRU register is XSAVE-managed state and can thus
be read and written by instructions in the XSAVE feature set.

PFEC.PK (bit 5) is defined as protection key violations.

The specification of Protection Keys can be found at SDM (4.6.2, volume 3)
http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-manual-325462.pdf.

Huaitong Han (9):
  x86/hvm: pkeys, add pkeys support for cpuid handling
  x86/hvm: pkeys, add the flag to enable Memory Protection Keys
  x86/hvm: pkeys, add pkeys support when setting CR4
  x86/hvm: pkeys, disable pkeys for guests in non-paging mode
  x86/hvm: pkeys, add functions to get pkeys value from PTE
  x86/hvm: pkeys, add functions to support PKRU access
  x86/hvm: pkeys, add pkeys support for guest_walk_tables
  x86/hvm: pkeys, add xstate support for pkeys
  x86/hvm: pkeys, add pkeys support for gva2gfn funcitons

 docs/misc/xen-command-line.markdown | 21 ++++++++++++
 tools/libxc/xc_cpufeature.h         |  2 ++
 tools/libxc/xc_cpuid_x86.c          |  6 ++--
 xen/arch/x86/cpu/common.c           |  5 +--
 xen/arch/x86/hvm/hvm.c              | 32 ++++++++++++++----
 xen/arch/x86/hvm/vmx/vmx.c          | 11 ++++---
 xen/arch/x86/mm/guest_walk.c        | 65 +++++++++++++++++++++++++++++++++++++
 xen/arch/x86/setup.c                |  7 ++++
 xen/arch/x86/xstate.c               | 18 ++++++++++
 xen/include/asm-x86/cpufeature.h    |  7 +++-
 xen/include/asm-x86/guest_pt.h      |  7 ++++
 xen/include/asm-x86/hvm/hvm.h       |  2 ++
 xen/include/asm-x86/page.h          |  5 +++
 xen/include/asm-x86/processor.h     | 15 +++++++++
 xen/include/asm-x86/x86_64/page.h   | 19 +++++++++++
 xen/include/asm-x86/xstate.h        |  5 ++-
 16 files changed, 210 insertions(+), 17 deletions(-)

-- 
2.4.3


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