Re: [PATCH v2 0/8] Support ACPI PSP on Hyper-V

From: Tom Lendacky
Date: Mon Feb 20 2023 - 09:50:08 EST


On 2/13/23 03:24, Jeremi Piotrowski wrote:
This patch series introduces support for discovering AMD's PSP from an ACPI
table and extends the CCP driver to allow binding to that device on x86. This
method of PSP discovery is used on Hyper-V when SNP isolation support is
exposed to the guest. There is no ACPI node associated with this PSP, so after
parsing the ASPT it is registered with the system as a platform_device.

I thought about putting psp.c in arch/x86/coco, but that directory is meant for
the (confidential) guest side of CoCo, not the supporting host side code.
It was kept in arch/x86/kernel because configuring the irq for the PSP through
the ACPI interface requires poking at bits from the architectural vector
domain.

This series is a prerequisite for nested SNP-host support on Hyper-V but is
independent of the SNP-host support patch set. Hyper-V only supports nested
SEV-SNP (not SEV or SEV-ES) so the PSP only supports a subset of the full PSP
command set. Without SNP-host support (which is not upstream yet), the only
PSP command that will succeed is SEV_PLATFORM_STATUS.


For the series:

Acked-by: Tom Lendacky <thomas.lendacky@xxxxxxx>

Probably want Boris to weigh in on whether he wants the new psp.c file located in arch/x86/kernel, though.

Changes since v1:
* move platform_device_add_data() call to commit that introduces psp device
* change psp dependency from CONFIG_AMD_MEM_ENCRYPT to CONFIG_KVM_AMD_SEV
* add blank lines, s/plat/platform/, remove variable initializers before first
use, remove masking/shifting where not needed
* dynamically allocate sev_vdata/psp_vdata structs instead of overwriting static
variables

Jeremi Piotrowski (8):
include/acpi: add definition of ASPT table
ACPI: ASPT: Add helper to parse table
x86/psp: Register PSP platform device when ASP table is present
x86/psp: Add IRQ support
crypto: cpp - Bind to psp platform device on x86
crypto: ccp - Add vdata for platform device
crypto: ccp - Skip DMA coherency check for platform psp
crypto: ccp - Allow platform device to be psp master device

arch/x86/kernel/Makefile | 1 +
arch/x86/kernel/psp.c | 219 ++++++++++++++++++++++++++++++
drivers/acpi/Makefile | 1 +
drivers/acpi/aspt.c | 104 ++++++++++++++
drivers/crypto/ccp/sp-dev.c | 66 +++++++++
drivers/crypto/ccp/sp-dev.h | 4 +
drivers/crypto/ccp/sp-pci.c | 48 -------
drivers/crypto/ccp/sp-platform.c | 76 ++++++++++-
include/acpi/actbl1.h | 46 +++++++
include/linux/platform_data/psp.h | 32 +++++
10 files changed, 548 insertions(+), 49 deletions(-)
create mode 100644 arch/x86/kernel/psp.c
create mode 100644 drivers/acpi/aspt.c
create mode 100644 include/linux/platform_data/psp.h