Mailing List Archive

Xen doesn't care (and indeed, cannot feasibly tell) whether a hypercall was
initiated from inside or outside a hypercall page.

For SEV-SNP/TDX encrypted VMs, use of a hypercall page would violate the
integrity properties wanted.

Explicitly state that the hypercall page is optional.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: George Dunlap <George.Dunlap@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien@xen.org>
CC: Anthony PERARD <anthony.perard@citrix.com>
---
docs/guest-guide/x86/hypercall-abi.rst | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/guest-guide/x86/hypercall-abi.rst b/docs/guest-guide/x86/hypercall-abi.rst
index 83890e1cb613..8004122ca49d 100644
--- a/docs/guest-guide/x86/hypercall-abi.rst
+++ b/docs/guest-guide/x86/hypercall-abi.rst
@@ -79,7 +79,8 @@ Hypercall Page
==============

The hypercall page is a page of guest RAM into which Xen will write suitable
-transfer stubs.
+transfer stubs. It is intended as a convenience for guests, but use of the
+hypercall page is not mandatory for making hypercalls to Xen.

Creating a hypercall page is an isolated operation from Xen's point of view.
It is the guests responsibility to ensure that the hypercall page, once

base-commit: 6cb501e3e6db36b1b4b6345f5af8adc0a291b404
--
2.30.2