xen64: save lots of registers (c24481e9) · Commits · 戴 / test

The Xen hypercall interface is allowed to trash any or all of the argument registers, so we need to be careful that the kernel state isn't damaged. On 32-bit kernels, the hypercall parameter registers same as a regparm function call, so we've got away without explicit clobbering so far. The 64-bit ABI defines lots of caller-save registers, so save them all for safety. We can trim this set later by re-distributing the responsibility for saving all these registers. Signed-off-by:

Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

include/asm-x86/paravirt.h

+22 −4

Original line number	Diff line number	Diff line
		@@ -1396,8 +1396,8 @@ extern struct paravirt_patch_site __parainstructions[],
		* caller saved registers but the argument parameter */
		#define PV_SAVE_REGS "pushq %%rdi;"
		#define PV_RESTORE_REGS "popq %%rdi;"
		#define PV_EXTRA_CLOBBERS EXTRA_CLOBBERS, "rcx" , "rdx"
		#define PV_VEXTRA_CLOBBERS EXTRA_CLOBBERS, "rdi", "rcx" , "rdx"
		#define PV_EXTRA_CLOBBERS EXTRA_CLOBBERS, "rcx" , "rdx", "rsi"
		#define PV_VEXTRA_CLOBBERS EXTRA_CLOBBERS, "rdi", "rcx" , "rdx", "rsi"
		#define PV_FLAGS_ARG "D"
		#endif

		@@ -1489,8 +1489,26 @@ static inline unsigned long __raw_local_irq_save(void)


		#ifdef CONFIG_X86_64
		#define PV_SAVE_REGS pushq %rax; pushq %rdi; pushq %rcx; pushq %rdx
		#define PV_RESTORE_REGS popq %rdx; popq %rcx; popq %rdi; popq %rax
		#define PV_SAVE_REGS \
		push %rax; \
		push %rcx; \
		push %rdx; \
		push %rsi; \
		push %rdi; \
		push %r8; \
		push %r9; \
		push %r10; \
		push %r11
		#define PV_RESTORE_REGS \
		pop %r11; \
		pop %r10; \
		pop %r9; \
		pop %r8; \
		pop %rdi; \
		pop %rsi; \
		pop %rdx; \
		pop %rcx; \
		pop %rax
		#define PARA_PATCH(struct, off) ((PARAVIRT_PATCH_##struct + (off)) / 8)
		#define PARA_SITE(ptype, clobbers, ops) _PVSITE(ptype, clobbers, ops, .quad, 8)
		#define PARA_INDIRECT(addr) *addr(%rip)

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