33 lines
1.2 KiB
Diff
33 lines
1.2 KiB
Diff
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References: bsc#995789
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# Commit 7b5cee79dad24e7006059667b02bd7de685d8ee5
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# Date 2016-09-08 16:39:46 +0100
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# Author Andrew Cooper <andrew.cooper3@citrix.com>
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# Committer Andrew Cooper <andrew.cooper3@citrix.com>
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hvm/fep: Allow testing of instructions crossing the -1 -> 0 virtual boundary
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The Force Emulation Prefix is named to follow its PV counterpart for cpuid or
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rdtsc, but isn't really an instruction prefix. It behaves as a break-out into
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Xen, with the purpose of emulating the next instruction in the current state.
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It is important to be able to test legal situations which occur in real
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hardware, including instruction which cross certain boundaries, and
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instructions starting at 0.
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Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
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Reviewed-by: Jan Beulich <jbeulich@suse.com>
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--- a/xen/arch/x86/hvm/hvm.c
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+++ b/xen/arch/x86/hvm/hvm.c
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@@ -3905,6 +3905,10 @@ void hvm_ud_intercept(struct cpu_user_re
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{
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regs->eip += sizeof(sig);
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regs->eflags &= ~X86_EFLAGS_RF;
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+
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+ /* Zero the upper 32 bits of %rip if not in long mode. */
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+ if ( !(hvm_long_mode_enabled(cur) && cs.attr.fields.l) )
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+ regs->eip = regs->_eip;
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}
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}
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