On 08/29/2018 01:23 PM, Brijesh Singh wrote: > 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@xxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxx> > Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> > Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx> > Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx> > 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(-) >
