[kvm-unit-tests,v2,00/16] Introduce SEV-SNP support

Message

Paluri, PavanKumar July 18, 2024, 12:49 p.m. UTC

This series introduces support for SNP features to KVM-Unit-Tests
environment. Goal of this work is to use KUT to build and develop a test
suite for KVM hypervisor with SEV-SNP support to test basic
functionality as well as determine whether hypervisor can handle edge
cases that a normal SNP guest otherwise wouldn't perform/request.

These patches are rebased on top of [1] and are available at:
https://github.com/pvpk1994/kvm-unit-tests-1/tree/SNP_RFC_v2

which are in turn rebased on kvm-unit-tests/master (201b9e8bdc84)

============
Patch Layout
============
Patches 1-2: Provide MMIO access support to the APIC page by unsetting
	     C-bit in guest page table for SEV-ES/SEV-SNP guest.

Patch 3: Renames SEV-ES's #VC handler to a more generic name that
	 applies to both SEV-ES and SEV-SNP. No functional change.

Patch 4: Adds support in x86/efi/run for running SEV-SNP unit tests
	 under UEFI

Patches 5-6: Adds support for SEV-SNP enablement and CC-blob discovery.

Patch 7: Sets up GHCB page table attributes for new page table.

Patches 8-12: Page state change conversions using MSR and GHCB protocol
	      approaches.

Patches 13-14: Page state change conversions from 2M intermixed states
	       to 2M Shared/Private states.

Patch 15: PSMASH/UNSMASH page state change requests on 2M large pages.

Patch 16: Injecting random non-zero page offsets via page state change
	  requests.

================================
Procedure to run this test-suite
================================
SEV-SNP KUT guest requires UEFI/OVMF to bootup. Information on how to
run the SEV-SNP tests with UEFI support can be found in
x86/efi/README.md introduced in this patchset.


Tested this patchset against the following: (Kernel, OVMF, QEMU):

Upstream QEMU:
 (commit: e2f346aa9864)
 Merge tag 'sdmmc-20240716' of https://github.com/philmd/qemu into staging 

Upstream OVMF:
 (commit: 11c50d6ca10a)
 MdeModulePkg/UfsBlockIoPei: Wait fDeviceInit Be Cleared by Devices

Upstream kernel: kvm/next
 (commit: 1c5a0b55abeb)
 Merge tag 'kvmarm-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

System can be configured as follows to run UEFI SNP tests:
    ./configure --enable-efi
     This will configure KUT to use #VC handler that it sets up once 
     GHCB page is mapped.

    ./configure --enable-efi --amdsev-efi-vc
    The above configuration option will build KUT and let SNP test use 
    #VC handler that is setup by OVMF throughout the lifetime of SNP 
    guest. 

The SNP tests introduced in this patchset run well with both the above
configuration options (--enable-efi and --enable-efi --amdsev-efi-vc).


Once configured, SEV-SNP unit tests can be tested as follows:
    export QEMU=/path/to/qemu-system-x86_64
    export EFI_UEFI=/path/to/OVMF.fd
    EFI_SNP=y ./x86/efi/run ./x86/amd_sev.efi

==========
References
==========
[1] https://lore.kernel.org/all/[e-mail]/

=========
Changelog
=========
v1 -> v2:
  * Rebased on AMD SEV-ES #VC handler patchset [1]
  * Rebased [1] on KUT's master (201b9e8bdc8b).
  * Introduced a new test where test issues PSMASH/UNSMASH page state 
    change requests on 2M ranges.
  * Introduced a new test where test injects random current page offsets 
    to examine how hypervisor handles page state change requests with
    non-zero page offsets for 2M large pages.
  * Implemented non-identity mappings for all page state change tests 
    (4K/2M) to avoid any odd side-effects arising due to page state 
    conversions on identity mapped pages.
  * Implemented a new helper (vmalloc_pages()) to allocate non-identity 
    mapped pages that would also be helpful for non-SNP related tests.
  * Introduced pgtable_va_to_pa() to help convert a guest virtual 
    address to guest physical address by doing page table walk that 
    would be helpful when we have non identity mapped pages where 
    virt_to_phys() won't work.
  * Introduced snp_free_pages() interface to help bring back all the 
    pages back to default guest-owned states before freeing up the 
    physical pages after the SNP tests finish.
  * Got rid of the check where end_entry is being forcefully truncated 
    to 252 when sizeof(struct snp_psc_desc) exceeds GHCB shared buffer 
    size. Instead, VMGEXIT_PSC_MAX_ENTRY is now calculated based on
    the size of the GHCB shared buffer.
  * Introduced add_psc_entry() helper to facilitate easy addition of a 
    new page state change entry for patches that need individual 
    entries to be added.
  * Dropped "RFC" tag.
  * v1: https://lore.kernel.org/all/[e-mail]/

Pavan Kumar Paluri (16):
  x86/apic: Use common library outb() implementation
  x86/apic: Add MMIO access support for SEV-ES/SNP guest with C-bit
    unset
  x86 AMD SEV-ES: Rename setup_amd_sev_es() to setup_vc_handler()
  x86/efi: Add support for running tests with UEFI in SEV-SNP
    environment
  x86 AMD SEV-SNP: Enable SEV-SNP support
  x86 AMD SEV-SNP: Add tests for presence of confidential computing blob
  x86 AMD SEV-ES: Set GHCB page attributes for a new page table
  x86 AMD SEV-SNP: Test Private->Shared page state changes using GHCB
    MSR
  x86: Introduce gva to gpa address translation helper
  x86: Add support for installing large pages
  x86 AMD SEV-SNP: Change guest pages from Private->Shared using GHCB
    NAE
  x86 AMD SEV-SNP: Change guest pages from Shared->Private using GHCB
    NAE
  x86 AMD SEV-SNP: Change guest pages from Intermix->Private using GHCB
    NAE
  x86 AMD SEV-SNP: Change guest pages from Intermix->Shared using GHCB
    NAE
  x86 AMD SEV-SNP: Issue PSMASH/UNSMASH PSC requests on 2M ranges
  x86 AMD SEV-SNP: Inject random cur_page offsets for 2M ranges

 lib/asm-generic/page.h |   2 +
 lib/linux/efi.h        |   1 +
 lib/x86/amd_sev.c      | 357 ++++++++++++++++++++++++++++++++++-
 lib/x86/amd_sev.h      | 124 +++++++++++-
 lib/x86/amd_sev_vc.c   |   2 +-
 lib/x86/apic.c         |  22 ++-
 lib/x86/setup.c        |  15 +-
 lib/x86/svm.h          |   1 +
 lib/x86/vm.c           |  70 +++++++
 lib/x86/vm.h           |   6 +
 x86/amd_sev.c          | 420 +++++++++++++++++++++++++++++++++++++++++
 x86/efi/README.md      |   6 +
 x86/efi/run            |  33 +++-
 13 files changed, 1038 insertions(+), 21 deletions(-)