--- x86/shim: Kconfig and command line options

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 334adfe35d19a5d5a2a8a5ba148fc6d76691a551..6e38f3e956faf1548915ee74d1cc334f13b4caba 100644 (file)
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -1445,6 +1445,17 @@ do; there may be other custom operating systems which do.  If you're
 certain you don't plan on having PV guests which use this feature,
 turning it off can reduce the attack surface.
 
+### pv-shim (x86)
+> `= <boolean>`
+
+> Default: `false`
+
+This option is intended for use by a toolstack, when choosing to run a PV
+guest compatibly inside an HVM container.
+
+In this mode, the kernel and initrd passed as modules to the hypervisor are
+constructed into a plain unprivileged PV domain.
+
 ### rcu-idle-timer-period-ms
 > `= <integer>`
 

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index c0b0bcdcb3ad46c822693f2b5a528083acdcdb6e..4953533f16c1a63186b22f177fd486822ef6a160 100644 (file)
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -133,6 +133,28 @@ config PVH_GUEST
        ---help---
          Support booting using the PVH ABI.
 
+         If unsure, say N.
+
+config PV_SHIM
+       def_bool n
+       prompt "PV Shim"
+       depends on PV && XEN_GUEST
+       ---help---
+         Build Xen with a mode which acts as a shim to allow PV guest to run
+         in an HVM/PVH container. This mode can only be enabled with command
+         line option.
+
+         If unsure, say N.
+
+config PV_SHIM_EXCLUSIVE
+       def_bool n
+       prompt "PV Shim Exclusive"
+       depends on PV_SHIM
+       ---help---
+         Build Xen in a way which unconditionally assumes PV_SHIM mode.  This
+         option is only intended for use when building a dedicated PV Shim
+         firmware, and will not function correctly in other scenarios.
+
          If unsure, say N.
 endmenu
 

diff --git a/xen/arch/x86/pv/Makefile b/xen/arch/x86/pv/Makefile
index bac2792aa2f7e9c2e5d69d915d67f943c710d6bd..65bca04175b7b7affb6879eea9b93f25ffdebadb 100644 (file)
--- a/xen/arch/x86/pv/Makefile
+++ b/xen/arch/x86/pv/Makefile
@@ -11,6 +11,7 @@ obj-y += iret.o
 obj-y += misc-hypercalls.o
 obj-y += mm.o
 obj-y += ro-page-fault.o
+obj-$(CONFIG_PV_SHIM) += shim.o
 obj-y += traps.o
 
 obj-bin-y += dom0_build.init.o

diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c
new file mode 100644 (file)
index 0000000..4d03735
--- /dev/null
+++ b/xen/arch/x86/pv/shim.c
@@ -0,0 +1,39 @@
+/******************************************************************************
+ * arch/x86/pv/shim.c
+ *
+ * Functionaltiy for PV Shim mode
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (c) 2017 Citrix Systems Ltd.
+ */
+#include <xen/init.h>
+#include <xen/types.h>
+
+#include <asm/apic.h>
+
+#ifndef CONFIG_PV_SHIM_EXCLUSIVE
+bool pv_shim;
+boolean_param("pv-shim", pv_shim);
+#endif
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */

diff --git a/xen/include/asm-x86/guest.h b/xen/include/asm-x86/guest.h
index 5abdb8c433ca6723a507c90bedfa640952135c73..a38c6b5b3f22f9402648cd8d3e5722df5f5ceeb6 100644 (file)
--- a/xen/include/asm-x86/guest.h
+++ b/xen/include/asm-x86/guest.h
@@ -22,6 +22,7 @@
 #include <asm/guest/hypercall.h>
 #include <asm/guest/pvh-boot.h>
 #include <asm/guest/xen.h>
+#include <asm/pv/shim.h>
 
 #endif /* __X86_GUEST_H__ */
 

diff --git a/xen/include/asm-x86/pv/shim.h b/xen/include/asm-x86/pv/shim.h
new file mode 100644 (file)
index 0000000..1468cfd
--- /dev/null
+++ b/xen/include/asm-x86/pv/shim.h
@@ -0,0 +1,42 @@
+/******************************************************************************
+ * asm-x86/guest/shim.h
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms and conditions of the GNU General Public
+ * License, version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (c) 2017 Citrix Systems Ltd.
+ */
+
+#ifndef __X86_PV_SHIM_H__
+#define __X86_PV_SHIM_H__
+
+#include <xen/types.h>
+
+#if defined(CONFIG_PV_SHIM_EXCLUSIVE)
+# define pv_shim 1
+#elif defined(CONFIG_PV_SHIM)
+extern bool pv_shim;
+#else
+# define pv_shim 0
+#endif /* CONFIG_PV_SHIM{,_EXCLUSIVE} */
+
+#endif /* __X86_PV_SHIM_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */