mirror of
https://github.com/torvalds/linux.git
synced 2026-07-31 19:47:08 +02:00
Linux kernel source tree
90cfe144c8
Add flag and hook to KVM's local APIC management to support determining whether or not a TDX guest has a pending IRQ. For TDX vCPUs, the virtual APIC page is owned by the TDX module and cannot be accessed by KVM. As a result, registers that are virtualized by the CPU, e.g. PPR, cannot be read or written by KVM. To deliver interrupts for TDX guests, KVM must send an IRQ to the CPU on the posted interrupt notification vector. And to determine if TDX vCPU has a pending interrupt, KVM must check if there is an outstanding notification. Return "no interrupt" in kvm_apic_has_interrupt() if the guest APIC is protected to short-circuit the various other flows that try to pull an IRQ out of the vAPIC, the only valid operation is querying _if_ an IRQ is pending, KVM can't do anything based on _which_ IRQ is pending. Intentionally omit sanity checks from other flows, e.g. PPR update, so as not to degrade non-TDX guests with unnecessary checks. A well-behaved KVM and userspace will never reach those flows for TDX guests, but reaching them is not fatal if something does go awry. For the TD exits not due to HLT TDCALL, skip checking RVI pending in tdx_protected_apic_has_interrupt(). Except for the guest being stupid (e.g., non-HLT TDCALL in an interrupt shadow), it's not even possible to have an interrupt in RVI that is fully unmasked. There is no any CPU flows that modify RVI in the middle of instruction execution. I.e. if RVI is non-zero, then either the interrupt has been pending since before the TD exit, or the instruction caused the TD exit is in an STI/SS shadow. KVM doesn't care about STI/SS shadows outside of the HALTED case. And if the interrupt was pending before TD exit, then it _must_ be blocked, otherwise the interrupt would have been serviced at the instruction boundary. For the HLT TDCALL case, it will be handled in a future patch when HLT TDCALL is supported. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com> Message-ID: <20250222014757.897978-2-binbin.wu@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.