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
On Thu, 10 Apr 2024, Andrew Cooper wrote: > 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> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> > --- > 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 >
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