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openSUSE:Evergreen:11.4
xen.548
25200-x86_64-trap-bounce-flags.patch
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File 25200-x86_64-trap-bounce-flags.patch of Package xen.548
References: bnc#757970 # HG changeset patch # User Jan Beulich <jbeulich@suse.com> # Date 1334669633 -7200 # Node ID 80f4113be5007f5b8a61048272193ce134b4fc28 # Parent 6092641e364428e7be20c9e23497d7a1fc535112 x86-64: fix #GP generation in assembly code When guest use of sysenter (64-bit PV guest) or syscall (32-bit PV guest) gets converted into a GP fault (due to no callback having got registered), we must - honor the GP fault handler's request the keep enabled or mask event delivery - not allow TBF_EXCEPTION to remain set past the generation of the (guest) exception in the vCPU's trap_bounce.flags, as that would otherwise allow for the next exception occurring in guest mode, should it happen to get handled in Xen itself, to nevertheless get bounced to the guest kernel. Also, just like compat mode syscall handling already did, native mode sysenter handling should, when converting to #GP, subtract 2 from the RIP present in the frame so that the guest's GP fault handler would see the fault pointing to the offending instruction instead of past it. Finally, since those exception generating code blocks needed to be modified anyway, convert them to make use of UNLIKELY_{START,END}(). Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Keir Fraser <keir@xen.org> --- a/xen/arch/x86/x86_64/asm-offsets.c +++ b/xen/arch/x86/x86_64/asm-offsets.c @@ -89,6 +89,8 @@ void __dummy__(void) arch.guest_context.trap_ctxt[TRAP_gp_fault].address); OFFSET(VCPU_gp_fault_sel, struct vcpu, arch.guest_context.trap_ctxt[TRAP_gp_fault].cs); + OFFSET(VCPU_gp_fault_flags, struct vcpu, + arch.guest_context.trap_ctxt[TRAP_gp_fault].flags); OFFSET(VCPU_kernel_sp, struct vcpu, arch.guest_context.kernel_sp); OFFSET(VCPU_kernel_ss, struct vcpu, arch.guest_context.kernel_ss); OFFSET(VCPU_guest_context_flags, struct vcpu, arch.guest_context.flags); --- a/xen/arch/x86/x86_64/compat/entry.S +++ b/xen/arch/x86/x86_64/compat/entry.S @@ -227,6 +227,7 @@ compat_failsafe_callback: ENTRY(compat_post_handle_exception) testb $TBF_EXCEPTION,TRAPBOUNCE_flags(%rdx) jz compat_test_all_events +.Lcompat_bounce_exception: call compat_create_bounce_frame movb $0,TRAPBOUNCE_flags(%rdx) jmp compat_test_all_events @@ -243,14 +244,15 @@ ENTRY(compat_syscall) 1: movq %rax,TRAPBOUNCE_eip(%rdx) movw %si,TRAPBOUNCE_cs(%rdx) movb %cl,TRAPBOUNCE_flags(%rdx) - call compat_create_bounce_frame - jmp compat_test_all_events + jmp .Lcompat_bounce_exception 2: movl $TRAP_gp_fault,UREGS_entry_vector(%rsp) subl $2,UREGS_rip(%rsp) movq VCPU_gp_fault_addr(%rbx),%rax movzwl VCPU_gp_fault_sel(%rbx),%esi - movb $(TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE|TBF_INTERRUPT),%cl movl $0,TRAPBOUNCE_error_code(%rdx) + testb $4,VCPU_gp_fault_flags(%rbx) + setnz %cl + leal TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE(,%rcx,TBF_INTERRUPT),%ecx jmp 1b ENTRY(compat_sysenter) --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -298,12 +298,13 @@ sysenter_eflags_saved: movb %cl,TRAPBOUNCE_flags(%rdx) testb $1,DOMAIN_is_32bit_pv(%rdi) jnz compat_sysenter - call create_bounce_frame - jmp test_all_events + jmp .Lbounce_exception 2: movl %eax,TRAPBOUNCE_error_code(%rdx) movq VCPU_gp_fault_addr(%rbx),%rax - movb $(TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE|TBF_INTERRUPT),%cl movl $TRAP_gp_fault,UREGS_entry_vector(%rsp) + testb $4,VCPU_gp_fault_flags(%rbx) + setnz %cl + leal TBF_EXCEPTION|TBF_EXCEPTION_ERRCODE(,%rcx,TBF_INTERRUPT),%ecx jmp 1b ENTRY(int80_direct_trap) @@ -490,6 +491,7 @@ handle_exception_saved: jnz compat_post_handle_exception testb $TBF_EXCEPTION,TRAPBOUNCE_flags(%rdx) jz test_all_events +.Lbounce_exception: call create_bounce_frame movb $0,TRAPBOUNCE_flags(%rdx) jmp test_all_events
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