tree bbd6818de62da3566193557fbee7fab32598b88a
parent 9cb024806610b9e57d97ace0709661f5e308d7f2
author Dan Williams <dan.j.williams@intel.com> 1760849592 -0700
committer Dan Williams <dan.j.williams@intel.com> 1763161695 -0800

x86/ioremap, resource: Introduce IORES_DESC_ENCRYPTED for encrypted PCI MMIO

PCIe Trusted Execution Environment Device Interface Security Protocol
(TDISP) arranges for a PCI device to support encrypted MMIO. In support of
that capability, ioremap() needs a mechanism to detect when a PCI device
has been dynamically transitioned into this secure state and enforce
encrypted MMIO mappings.

Teach ioremap() about a new IORES_DESC_ENCRYPTED type that supplements the
existing PCI Memory Space (MMIO) BAR resources. The proposal is that a
resource, "PCI MMIO Encrypted", with this description type is injected by
the PCI/TSM core for each PCI device BAR that is to be protected.

Unlike the existing encryption determination which is "implied with a
silent fallback to an unencrypted mapping", this indication is "explicit
with an expectation that the request fails instead of fallback".
IORES_MUST_ENCRYPT is added to manage this expectation.

Given that "PCI MMIO Encrypted" is an additional resource in the tree, the
IORESOURCE_BUSY flag will only be set on a descendant/child of that
resource. That means it cannot share the same walk as the check for "System
RAM". Add walk_iomem_res_desc() to check if any IORES_DESC_ENCRYPTED
intersects the ioremap() range and set IORES_MUST_ENCRYPT accordingly.

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>