lkml.org 
[lkml]   [2018]   [Sep]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[PATCH v4 0/4] x86: Fix SEV guest regression
Date
The following commit

"
x86/kvmclock: Remove memblock dependency

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=368a540e0232ad446931f5a4e8a5e06f69f21343
"

introduced SEV guest regression.

The guest physical address holding the wall_clock and hv_clock_boot
are shared with the hypervisor must be mapped with C=0 when SEV
is active. To clear the C-bit we use kernel_physical_mapping_init() to
split the large pages. The above commit moved the kvmclock initialization
very early and kernel_physical_mapping_init() fails to allocate memory
while spliting the large page.

To solve it, we add a special .data..decrypted section, this section can be
used to hold the shared variables. Early boot code maps this section with
C=0. The section is pmd aligned and sized to avoid the need to split the pages.
Caller can use __decrypted attribute to add the variables in .data..decrypted
section.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>

Changes since v3:
- commit message improvements (based on Sean's feedback)

Changes since v2:
- commit message and code comment improvements (based on Boris feedback)
- move sme_populate_pgd fixes in new patch.
- drop stable Cc - will submit to stable after patch is upstreamed.

Changes since v1:
- move the logic to re-arrange mapping in new patch
- move the definition of __start_data_* in mem_encrypt.h
- map the workarea buffer as encrypted when SEV is enabled
- enhance the sme_populate_pgd to update the pte/pmd flags when mapping exist

Brijesh Singh (4):
x86/mm: Restructure sme_encrypt_kernel()
x86/mm: fix sme_populate_pgd() to update page flags
x86/mm: add .data..decrypted section to hold shared variables
x86/kvm: use __decrypted attribute in shared variables

arch/x86/include/asm/mem_encrypt.h | 6 +
arch/x86/kernel/head64.c | 11 ++
arch/x86/kernel/kvmclock.c | 30 ++++-
arch/x86/kernel/vmlinux.lds.S | 17 +++
arch/x86/mm/mem_encrypt_identity.c | 232 +++++++++++++++++++++++++++----------
5 files changed, 229 insertions(+), 67 deletions(-)

--
2.7.4

\
 
 \ /
  Last update: 2018-09-04 03:35    [W:0.069 / U:1.492 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site