From 2b3218eb6bf27d3b66885dde8ae05e4e7864370d Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Mon, 28 May 2018 15:16:37 +0000 Subject: [PATCH] x86/emul: Unfold %cr4.de handling in x86emul_read_dr() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit No functional change (as curr->arch.debugreg[5] is zero when DE is clear), but this change simplifies the following patch. Signed-off-by: Andrew Cooper Acked-by: Jan Beulich Reviewed-by: Roger Pau Monné --- xen/arch/x86/x86_emulate.c | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/xen/arch/x86/x86_emulate.c b/xen/arch/x86/x86_emulate.c index 532b7e04e1..e1153f76b2 100644 --- a/xen/arch/x86/x86_emulate.c +++ b/xen/arch/x86/x86_emulate.c @@ -101,23 +101,29 @@ int x86emul_read_dr(unsigned int reg, unsigned long *val, switch ( reg ) { case 0 ... 3: - case 6: *val = curr->arch.debugreg[reg]; break; + case 4: + if ( curr->arch.pv.ctrlreg[4] & X86_CR4_DE ) + goto ud_fault; + + /* Fallthrough */ + case 6: + *val = curr->arch.debugreg[6]; + break; + + case 5: + if ( curr->arch.pv.ctrlreg[4] & X86_CR4_DE ) + goto ud_fault; + + /* Fallthrough */ case 7: *val = (curr->arch.debugreg[7] | curr->arch.debugreg[5]); break; - case 4 ... 5: - if ( !(curr->arch.pv.ctrlreg[4] & X86_CR4_DE) ) - { - *val = curr->arch.debugreg[reg + 2]; - break; - } - - /* Fallthrough */ + ud_fault: default: if ( ctxt ) x86_emul_hw_exception(TRAP_invalid_op, X86_EVENT_NO_EC, ctxt); -- 2.30.2