b6f084ca55
Add a VM-Exit handler to trap-and-execute EINIT when SGX LC is enabled in the host. When SGX LC is enabled, the host kernel may rewrite the hardware values at will, e.g. to launch enclaves with different signers, thus KVM needs to intercept EINIT to ensure it is executed with the correct LE hash (even if the guest sees a hardwired hash). Switching the LE hash MSRs on VM-Enter/VM-Exit is not a viable option as writing the MSRs is prohibitively expensive, e.g. on SKL hardware each WRMSR is ~400 cycles. And because EINIT takes tens of thousands of cycles to execute, the ~1500 cycle overhead to trap-and-execute EINIT is unlikely to be noticed by the guest, let alone impact its overall SGX performance. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Kai Huang <kai.huang@intel.com> Message-Id: <57c92fa4d2083eb3be9e6355e3882fc90cffea87.1618196135.git.kai.huang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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 Restructured Text 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.