From 16d5163f338753fb93b1809e067da5d27d540fbc Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 4 Feb 2021 17:24:57 -0800 Subject: [PATCH] KVM: x86: Remove misleading DR6/DR7 adjustments from RSM emulation Drop the DR6/7 volatile+fixed bits adjustments in RSM emulation, which are redundant and misleading. The necessary adjustments are made by kvm_set_dr(), which properly sets the fixed bits that are conditional on the vCPU model. Note, KVM incorrectly reads only bits 31:0 of the DR6/7 fields when emulating RSM on x86-64. On the plus side for this change, that bug makes removing "& DRx_VOLATILE" a nop. No functional change intended. Signed-off-by: Sean Christopherson Message-Id: <20210205012458.3872687-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 612ee69..b5f433d 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2506,12 +2506,12 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, val = GET_SMSTATE(u32, smstate, 0x7fcc); - if (ctxt->ops->set_dr(ctxt, 6, (val & DR6_VOLATILE) | DR6_FIXED_1)) + if (ctxt->ops->set_dr(ctxt, 6, val)) return X86EMUL_UNHANDLEABLE; val = GET_SMSTATE(u32, smstate, 0x7fc8); - if (ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1)) + if (ctxt->ops->set_dr(ctxt, 7, val)) return X86EMUL_UNHANDLEABLE; selector = GET_SMSTATE(u32, smstate, 0x7fc4); @@ -2566,12 +2566,12 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, val = GET_SMSTATE(u32, smstate, 0x7f68); - if (ctxt->ops->set_dr(ctxt, 6, (val & DR6_VOLATILE) | DR6_FIXED_1)) + if (ctxt->ops->set_dr(ctxt, 6, val)) return X86EMUL_UNHANDLEABLE; val = GET_SMSTATE(u32, smstate, 0x7f60); - if (ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1)) + if (ctxt->ops->set_dr(ctxt, 7, val)) return X86EMUL_UNHANDLEABLE; cr0 = GET_SMSTATE(u64, smstate, 0x7f58); -- 2.7.4