From c0f890cd9d5fd2c17a1e3110cb26f98c90ce8429 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Thu, 11 Apr 2024 15:37:57 +0100 Subject: [PATCH] docs/hypercall-abi: State that the hypercall page is optional Xen doesn't care (and indeed, cannot feasibly tell) whether a hypercall was initiated using the hypercall page or not. 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 Reviewed-by: Stefano Stabellini --- 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 83890e1cb6..8004122ca4 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 -- 2.39.5