| Message ID | 20240411150458.1726116-1-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | docs/hypercall-abi: State that the hypercall page is optional | expand |
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 >
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
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(-) base-commit: 6cb501e3e6db36b1b4b6345f5af8adc0a291b404