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x86/xen: use new hypercall functions instead of hypercall page

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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@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Co-developed-by: Peter Zijlstra <peterz@infradead.org>
Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com>
This commit is contained in:
Juergen Gross 2024-10-17 14:47:13 +02:00
parent b4845bb638
commit b1c2cb86f4
1 changed files with 20 additions and 13 deletions
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33
arch/x86/include/asm/xen/hypercall.h
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@ -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]; } hypercall_page[];
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_hypercall_func);
__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_hypercall_func);
__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_hypercall_func);
__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_hypercall_func);
__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_hypercall_func);
__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;