5.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Juergen Gross <jgross@xxxxxxxx>
commit b1c2cb86f4a7861480ad54bb9a58df3cbebf8e92 upstream.
Call the Xen hypervisor via the new xen_hypercall_func static-call
instead of the hypercall page.
This is part of XSA-466 / CVE-2024-53241.
Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Co-developed-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Co-developed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/xen/hypercall.h | 33 ++++++++++++++++++++-------------
1 file changed, 20 insertions(+), 13 deletions(-)
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -39,9 +39,11 @@
#include <linux/string.h>
#include <linux/types.h>
#include <linux/pgtable.h>
+#include <linux/instrumentation.h>
#include <trace/events/xen.h>
+#include <asm/alternative.h>
#include <asm/page.h>
#include <asm/smap.h>
#include <asm/nospec-branch.h>
@@ -91,9 +93,17 @@ extern struct { char _entry[32]; } hyper
void xen_hypercall_func(void);
DECLARE_STATIC_CALL(xen_hypercall, xen_hypercall_func);
-#define __HYPERCALL "call hypercall_page+%c[offset]"
-#define __HYPERCALL_ENTRY(x) \
- [offset] "i" (__HYPERVISOR_##x * sizeof(hypercall_page[0]))
+#ifdef MODULE
+#define __ADDRESSABLE_xen_hypercall
+#else
+#define __ADDRESSABLE_xen_hypercall __ADDRESSABLE_ASM_STR(__SCK__xen_hypercall)
+#endif
+
+#define __HYPERCALL \
+ __ADDRESSABLE_xen_hypercall \
+ "call __SCT__xen_hypercall"
+
+#define __HYPERCALL_ENTRY(x) "a" (x)
#ifdef CONFIG_X86_32
#define __HYPERCALL_RETREG "eax"
@@ -151,7 +161,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h
__HYPERCALL_0ARG(); \
asm volatile (__HYPERCALL \
: __HYPERCALL_0PARAM \
- : __HYPERCALL_ENTRY(name) \
+ : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \
: __HYPERCALL_CLOBBER0); \
(type)__res; \
})
@@ -162,7 +172,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h
__HYPERCALL_1ARG(a1); \
asm volatile (__HYPERCALL \
: __HYPERCALL_1PARAM \
- : __HYPERCALL_ENTRY(name) \
+ : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \
: __HYPERCALL_CLOBBER1); \
(type)__res; \
})
@@ -173,7 +183,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h
__HYPERCALL_2ARG(a1, a2); \
asm volatile (__HYPERCALL \
: __HYPERCALL_2PARAM \
- : __HYPERCALL_ENTRY(name) \
+ : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \
: __HYPERCALL_CLOBBER2); \
(type)__res; \
})
@@ -184,7 +194,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h
__HYPERCALL_3ARG(a1, a2, a3); \
asm volatile (__HYPERCALL \
: __HYPERCALL_3PARAM \
- : __HYPERCALL_ENTRY(name) \
+ : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \
: __HYPERCALL_CLOBBER3); \
(type)__res; \
})
@@ -195,7 +205,7 @@ DECLARE_STATIC_CALL(xen_hypercall, xen_h
__HYPERCALL_4ARG(a1, a2, a3, a4); \
asm volatile (__HYPERCALL \
: __HYPERCALL_4PARAM \
- : __HYPERCALL_ENTRY(name) \
+ : __HYPERCALL_ENTRY(__HYPERVISOR_ ## name) \
: __HYPERCALL_CLOBBER4); \
(type)__res; \
})
@@ -209,12 +219,9 @@ xen_single_call(unsigned int call,
__HYPERCALL_DECLS;
__HYPERCALL_5ARG(a1, a2, a3, a4, a5);
- if (call >= PAGE_SIZE / sizeof(hypercall_page[0]))
- return -EINVAL;
-
- asm volatile(CALL_NOSPEC
+ asm volatile(__HYPERCALL
: __HYPERCALL_5PARAM
- : [thunk_target] "a" (&hypercall_page[call])
+ : __HYPERCALL_ENTRY(call)
: __HYPERCALL_CLOBBER5);
return (long)__res;
