Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "A new testcase for guest debugging (gdbstub) that exposed a bunch of
  bugs, mostly for AMD processors. And a few other x86 fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: Fix off-by-one error in kvm_vcpu_ioctl_x86_setup_mce
  KVM: x86: Fix pkru save/restore when guest CR4.PKE=0, move it to x86.c
  KVM: SVM: Disable AVIC before setting V_IRQ
  KVM: Introduce kvm_make_all_cpus_request_except()
  KVM: VMX: pass correct DR6 for GD userspace exit
  KVM: x86, SVM: isolate vcpu->arch.dr6 from vmcb->save.dr6
  KVM: SVM: keep DR6 synchronized with vcpu->arch.dr6
  KVM: nSVM: trap #DB and #BP to userspace if guest debugging is on
  KVM: selftests: Add KVM_SET_GUEST_DEBUG test
  KVM: X86: Fix single-step with KVM_SET_GUEST_DEBUG
  KVM: X86: Set RTM for DB_VECTOR too for KVM_EXIT_DEBUG
  KVM: x86: fix DR6 delivery for various cases of #DB injection
  KVM: X86: Declare KVM_CAP_SET_GUEST_DEBUG properly

12 files changed, 325 insertions, 88 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0dea9f122bb9..0a6b35353fc7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -578,6 +578,7 @@ struct kvm_vcpu_arch {
 	unsigned long cr4;
 	unsigned long cr4_guest_owned_bits;
 	unsigned long cr8;
+	u32 host_pkru;
 	u32 pkru;
 	u32 hflags;
 	u64 efer;
@@ -1093,8 +1094,6 @@ struct kvm_x86_ops {
 	void (*set_idt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
 	void (*get_gdt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
 	void (*set_gdt)(struct kvm_vcpu *vcpu, struct desc_ptr *dt);
-	u64 (*get_dr6)(struct kvm_vcpu *vcpu);
-	void (*set_dr6)(struct kvm_vcpu *vcpu, unsigned long value);
 	void (*sync_dirty_debug_regs)(struct kvm_vcpu *vcpu);
 	void (*set_dr7)(struct kvm_vcpu *vcpu, unsigned long value);
 	void (*cache_reg)(struct kvm_vcpu *vcpu, enum kvm_reg reg);
@@ -1449,6 +1448,7 @@ bool kvm_rdpmc(struct kvm_vcpu *vcpu);
 
 void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr);
 void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
+void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr, unsigned long payload);
 void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr);
 void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
 void kvm_inject_page_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault);
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index bcefa9d4e57e..54d4b98b49e1 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1427,7 +1427,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
 	 */
 	kvm_make_vcpus_request_mask(kvm,
 				    KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP,
-				    vcpu_mask, &hv_vcpu->tlb_flush);
+				    NULL, vcpu_mask, &hv_vcpu->tlb_flush);
 
 ret_success:
 	/* We always do full TLB flush, set rep_done = rep_cnt. */
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 90a1ca939627..9a2a62e5afeb 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 
 #include <asm/msr-index.h>
+#include <asm/debugreg.h>
 
 #include "kvm_emulate.h"
 #include "trace.h"
@@ -267,7 +268,7 @@ void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
 	svm->vmcb->save.rsp = nested_vmcb->save.rsp;
 	svm->vmcb->save.rip = nested_vmcb->save.rip;
 	svm->vmcb->save.dr7 = nested_vmcb->save.dr7;
-	svm->vmcb->save.dr6 = nested_vmcb->save.dr6;
+	svm->vcpu.arch.dr6  = nested_vmcb->save.dr6;
 	svm->vmcb->save.cpl = nested_vmcb->save.cpl;
 
 	svm->nested.vmcb_msrpm = nested_vmcb->control.msrpm_base_pa & ~0x0fffULL;
@@ -482,7 +483,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	nested_vmcb->save.rsp    = vmcb->save.rsp;
 	nested_vmcb->save.rax    = vmcb->save.rax;
 	nested_vmcb->save.dr7    = vmcb->save.dr7;
-	nested_vmcb->save.dr6    = vmcb->save.dr6;
+	nested_vmcb->save.dr6    = svm->vcpu.arch.dr6;
 	nested_vmcb->save.cpl    = vmcb->save.cpl;
 
 	nested_vmcb->control.int_ctl           = vmcb->control.int_ctl;
@@ -606,26 +607,45 @@ static int nested_svm_exit_handled_msr(struct vcpu_svm *svm)
 /* DB exceptions for our internal use must not cause vmexit */
 static int nested_svm_intercept_db(struct vcpu_svm *svm)
 {
-	unsigned long dr6;
+	unsigned long dr6 = svm->vmcb->save.dr6;
+
+	/* Always catch it and pass it to userspace if debugging.  */
+	if (svm->vcpu.guest_debug &
+	    (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))
+		return NESTED_EXIT_HOST;
 
 	/* if we're not singlestepping, it's not ours */
 	if (!svm->nmi_singlestep)
-		return NESTED_EXIT_DONE;
+		goto reflected_db;
 
 	/* if it's not a singlestep exception, it's not ours */
-	if (kvm_get_dr(&svm->vcpu, 6, &dr6))
-		return NESTED_EXIT_DONE;
 	if (!(dr6 & DR6_BS))
-		return NESTED_EXIT_DONE;
+		goto reflected_db;
 
 	/* if the guest is singlestepping, it should get the vmexit */
 	if (svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF) {
 		disable_nmi_singlestep(svm);
-		return NESTED_EXIT_DONE;
+		goto reflected_db;
 	}
 
 	/* it's ours, the nested hypervisor must not see this one */
 	return NESTED_EXIT_HOST;
+
+reflected_db:
+	/*
+	 * Synchronize guest DR6 here just like in kvm_deliver_exception_payload;
+	 * it will be moved into the nested VMCB by nested_svm_vmexit.  Once
+	 * exceptions will be moved to svm_check_nested_events, all this stuff
+	 * will just go away and we could just return NESTED_EXIT_HOST
+	 * unconditionally.  db_interception will queue the exception, which
+	 * will be processed by svm_check_nested_events if a nested vmexit is
+	 * required, and we will just use kvm_deliver_exception_payload to copy
+	 * the payload to DR6 before vmexit.
+	 */
+	WARN_ON(svm->vcpu.arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT);
+	svm->vcpu.arch.dr6 &= ~(DR_TRAP_BITS | DR6_RTM);
+	svm->vcpu.arch.dr6 |= dr6 & ~DR6_FIXED_1;
+	return NESTED_EXIT_DONE;
 }
 
 static int nested_svm_intercept_ioio(struct vcpu_svm *svm)
@@ -682,6 +702,9 @@ static int nested_svm_intercept(struct vcpu_svm *svm)
 		if (svm->nested.intercept_exceptions & excp_bits) {
 			if (exit_code == SVM_EXIT_EXCP_BASE + DB_VECTOR)
 				vmexit = nested_svm_intercept_db(svm);
+			else if (exit_code == SVM_EXIT_EXCP_BASE + BP_VECTOR &&
+				 svm->vcpu.guest_debug & KVM_GUESTDBG_USE_SW_BP)
+				vmexit = NESTED_EXIT_HOST;
 			else
 				vmexit = NESTED_EXIT_DONE;
 		}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 38f6aeefeb55..a862c768fd54 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1672,17 +1672,14 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd)
 	mark_dirty(svm->vmcb, VMCB_ASID);
 }
 
-static u64 svm_get_dr6(struct kvm_vcpu *vcpu)
+static void svm_set_dr6(struct vcpu_svm *svm, unsigned long value)
 {
-	return to_svm(vcpu)->vmcb->save.dr6;
-}
-
-static void svm_set_dr6(struct kvm_vcpu *vcpu, unsigned long value)
-{
-	struct vcpu_svm *svm = to_svm(vcpu);
+	struct vmcb *vmcb = svm->vmcb;
 
-	svm->vmcb->save.dr6 = value;
-	mark_dirty(svm->vmcb, VMCB_DR);
+	if (unlikely(value != vmcb->save.dr6)) {
+		vmcb->save.dr6 = value;
+		mark_dirty(vmcb, VMCB_DR);
+	}
 }
 
 static void svm_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
@@ -1693,9 +1690,12 @@ static void svm_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
 	get_debugreg(vcpu->arch.db[1], 1);
 	get_debugreg(vcpu->arch.db[2], 2);
 	get_debugreg(vcpu->arch.db[3], 3);
-	vcpu->arch.dr6 = svm_get_dr6(vcpu);
+	/*
+	 * We cannot reset svm->vmcb->save.dr6 to DR6_FIXED_1|DR6_RTM here,
+	 * because db_interception might need it.  We can do it before vmentry.
+	 */
+	vcpu->arch.dr6 = svm->vmcb->save.dr6;
 	vcpu->arch.dr7 = svm->vmcb->save.dr7;
-
 	vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_WONT_EXIT;
 	set_dr_intercepts(svm);
 }
@@ -1739,7 +1739,8 @@ static int db_interception(struct vcpu_svm *svm)
 	if (!(svm->vcpu.guest_debug &
 	      (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP)) &&
 		!svm->nmi_singlestep) {
-		kvm_queue_exception(&svm->vcpu, DB_VECTOR);
+		u32 payload = (svm->vmcb->save.dr6 ^ DR6_RTM) & ~DR6_FIXED_1;
+		kvm_queue_exception_p(&svm->vcpu, DB_VECTOR, payload);
 		return 1;
 	}
 
@@ -3317,6 +3318,15 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 
 	svm->vmcb->save.cr2 = vcpu->arch.cr2;
 
+	/*
+	 * Run with all-zero DR6 unless needed, so that we can get the exact cause
+	 * of a #DB.
+	 */
+	if (unlikely(svm->vcpu.arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT))
+		svm_set_dr6(svm, vcpu->arch.dr6);
+	else
+		svm_set_dr6(svm, DR6_FIXED_1 | DR6_RTM);
+
 	clgi();
 	kvm_load_guest_xsave_state(vcpu);
 
@@ -3931,8 +3941,6 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.set_idt = svm_set_idt,
 	.get_gdt = svm_get_gdt,
 	.set_gdt = svm_set_gdt,
-	.get_dr6 = svm_get_dr6,
-	.set_dr6 = svm_set_dr6,
 	.set_dr7 = svm_set_dr7,
 	.sync_dirty_debug_regs = svm_sync_dirty_debug_regs,
 	.cache_reg = svm_cache_reg,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index c2c6335a998c..89c766fad889 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1372,7 +1372,6 @@ void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	vmx_vcpu_pi_load(vcpu, cpu);
 
-	vmx->host_pkru = read_pkru();
 	vmx->host_debugctlmsr = get_debugctlmsr();
 }
 
@@ -4677,15 +4676,13 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
 		dr6 = vmcs_readl(EXIT_QUALIFICATION);
 		if (!(vcpu->guest_debug &
 		      (KVM_GUESTDBG_SINGLESTEP | KVM_GUESTDBG_USE_HW_BP))) {
-			vcpu->arch.dr6 &= ~DR_TRAP_BITS;
-			vcpu->arch.dr6 |= dr6 | DR6_RTM;
 			if (is_icebp(intr_info))
 				WARN_ON(!skip_emulated_instruction(vcpu));
 
-			kvm_queue_exception(vcpu, DB_VECTOR);
+			kvm_queue_exception_p(vcpu, DB_VECTOR, dr6);
 			return 1;
 		}
-		kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1;
+		kvm_run->debug.arch.dr6 = dr6 | DR6_FIXED_1 | DR6_RTM;
 		kvm_run->debug.arch.dr7 = vmcs_readl(GUEST_DR7);
 		/* fall through */
 	case BP_VECTOR:
@@ -4929,16 +4926,14 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 		 * guest debugging itself.
 		 */
 		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
-			vcpu->run->debug.arch.dr6 = vcpu->arch.dr6;
+			vcpu->run->debug.arch.dr6 = DR6_BD | DR6_RTM | DR6_FIXED_1;
 			vcpu->run->debug.arch.dr7 = dr7;
 			vcpu->run->debug.arch.pc = kvm_get_linear_rip(vcpu);
 			vcpu->run->debug.arch.exception = DB_VECTOR;
 			vcpu->run->exit_reason = KVM_EXIT_DEBUG;
 			return 0;
 		} else {
-			vcpu->arch.dr6 &= ~DR_TRAP_BITS;
-			vcpu->arch.dr6 |= DR6_BD | DR6_RTM;
-			kvm_queue_exception(vcpu, DB_VECTOR);
+			kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BD);
 			return 1;
 		}
 	}
@@ -4969,15 +4964,6 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 	return kvm_skip_emulated_instruction(vcpu);
 }
 
-static u64 vmx_get_dr6(struct kvm_vcpu *vcpu)
-{
-	return vcpu->arch.dr6;
-}
-
-static void vmx_set_dr6(struct kvm_vcpu *vcpu, unsigned long val)
-{
-}
-
 static void vmx_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
 {
 	get_debugreg(vcpu->arch.db[0], 0);
@@ -6577,11 +6563,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	kvm_load_guest_xsave_state(vcpu);
 
-	if (static_cpu_has(X86_FEATURE_PKU) &&
-	    kvm_read_cr4_bits(vcpu, X86_CR4_PKE) &&
-	    vcpu->arch.pkru != vmx->host_pkru)
-		__write_pkru(vcpu->arch.pkru);
-
 	pt_guest_enter(vmx);
 
 	if (vcpu_to_pmu(vcpu)->version)
@@ -6671,18 +6652,6 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
 
 	pt_guest_exit(vmx);
 
-	/*
-	 * eager fpu is enabled if PKEY is supported and CR4 is switched
-	 * back on host, so it is safe to read guest PKRU from current
-	 * XSAVE.
-	 */
-	if (static_cpu_has(X86_FEATURE_PKU) &&
-	    kvm_read_cr4_bits(vcpu, X86_CR4_PKE)) {
-		vcpu->arch.pkru = rdpkru();
-		if (vcpu->arch.pkru != vmx->host_pkru)
-			__write_pkru(vmx->host_pkru);
-	}
-
 	kvm_load_host_xsave_state(vcpu);
 
 	vmx->nested.nested_run_pending = 0;
@@ -7740,8 +7709,6 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = {
 	.set_idt = vmx_set_idt,
 	.get_gdt = vmx_get_gdt,
 	.set_gdt = vmx_set_gdt,
-	.get_dr6 = vmx_get_dr6,
-	.set_dr6 = vmx_set_dr6,
 	.set_dr7 = vmx_set_dr7,
 	.sync_dirty_debug_regs = vmx_sync_dirty_debug_regs,
 	.cache_reg = vmx_cache_reg,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d786c7d27ce5..c17e6eb9ad43 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -572,11 +572,12 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr)
 }
 EXPORT_SYMBOL_GPL(kvm_requeue_exception);
 
-static void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr,
-				  unsigned long payload)
+void kvm_queue_exception_p(struct kvm_vcpu *vcpu, unsigned nr,
+			   unsigned long payload)
 {
 	kvm_multiple_exception(vcpu, nr, false, 0, true, payload, false);
 }
+EXPORT_SYMBOL_GPL(kvm_queue_exception_p);
 
 static void kvm_queue_exception_e_p(struct kvm_vcpu *vcpu, unsigned nr,
 				    u32 error_code, unsigned long payload)
@@ -836,11 +837,25 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu)
 		    vcpu->arch.ia32_xss != host_xss)
 			wrmsrl(MSR_IA32_XSS, vcpu->arch.ia32_xss);
 	}
+
+	if (static_cpu_has(X86_FEATURE_PKU) &&
+	    (kvm_read_cr4_bits(vcpu, X86_CR4_PKE) ||
+	     (vcpu->arch.xcr0 & XFEATURE_MASK_PKRU)) &&
+	    vcpu->arch.pkru != vcpu->arch.host_pkru)
+		__write_pkru(vcpu->arch.pkru);
 }
 EXPORT_SYMBOL_GPL(kvm_load_guest_xsave_state);
 
 void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu)
 {
+	if (static_cpu_has(X86_FEATURE_PKU) &&
+	    (kvm_read_cr4_bits(vcpu, X86_CR4_PKE) ||
+	     (vcpu->arch.xcr0 & XFEATURE_MASK_PKRU))) {
+		vcpu->arch.pkru = rdpkru();
+		if (vcpu->arch.pkru != vcpu->arch.host_pkru)
+			__write_pkru(vcpu->arch.host_pkru);
+	}
+
 	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) {
 
 		if (vcpu->arch.xcr0 != host_xcr0)
@@ -1045,12 +1060,6 @@ static void kvm_update_dr0123(struct kvm_vcpu *vcpu)
 	}
 }
 
-static void kvm_update_dr6(struct kvm_vcpu *vcpu)
-{
-	if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
-		kvm_x86_ops.set_dr6(vcpu, vcpu->arch.dr6);
-}
-
 static void kvm_update_dr7(struct kvm_vcpu *vcpu)
 {
 	unsigned long dr7;
@@ -1090,7 +1099,6 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
 		if (val & 0xffffffff00000000ULL)
 			return -1; /* #GP */
 		vcpu->arch.dr6 = (val & DR6_VOLATILE) | kvm_dr6_fixed(vcpu);
-		kvm_update_dr6(vcpu);
 		break;
 	case 5:
 		/* fall through */
@@ -1126,10 +1134,7 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
 	case 4:
 		/* fall through */
 	case 6:
-		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
-			*val = vcpu->arch.dr6;
-		else
-			*val = kvm_x86_ops.get_dr6(vcpu);
+		*val = vcpu->arch.dr6;
 		break;
 	case 5:
 		/* fall through */
@@ -3558,6 +3563,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	kvm_x86_ops.vcpu_load(vcpu, cpu);
 
+	/* Save host pkru register if supported */
+	vcpu->arch.host_pkru = read_pkru();
+
 	/* Apply any externally detected TSC adjustments (due to suspend) */
 	if (unlikely(vcpu->arch.tsc_offset_adjustment)) {
 		adjust_tsc_offset_host(vcpu, vcpu->arch.tsc_offset_adjustment);
@@ -3751,7 +3759,7 @@ static int kvm_vcpu_ioctl_x86_setup_mce(struct kvm_vcpu *vcpu,
 	unsigned bank_num = mcg_cap & 0xff, bank;
 
 	r = -EINVAL;
-	if (!bank_num || bank_num >= KVM_MAX_MCE_BANKS)
+	if (!bank_num || bank_num > KVM_MAX_MCE_BANKS)
 		goto out;
 	if (mcg_cap & ~(kvm_mce_cap_supported | 0xff | 0xff0000))
 		goto out;
@@ -4009,7 +4017,6 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
 	memcpy(vcpu->arch.db, dbgregs->db, sizeof(vcpu->arch.db));
 	kvm_update_dr0123(vcpu);
 	vcpu->arch.dr6 = dbgregs->dr6;
-	kvm_update_dr6(vcpu);
 	vcpu->arch.dr7 = dbgregs->dr7;
 	kvm_update_dr7(vcpu);
 
@@ -6659,7 +6666,7 @@ static int kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu)
 
 	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {
 		kvm_run->debug.arch.dr6 = DR6_BS | DR6_FIXED_1 | DR6_RTM;
-		kvm_run->debug.arch.pc = vcpu->arch.singlestep_rip;
+		kvm_run->debug.arch.pc = kvm_get_linear_rip(vcpu);
 		kvm_run->debug.arch.exception = DB_VECTOR;
 		kvm_run->exit_reason = KVM_EXIT_DEBUG;
 		return 0;
@@ -6719,9 +6726,7 @@ static bool kvm_vcpu_check_breakpoint(struct kvm_vcpu *vcpu, int *r)
 					   vcpu->arch.db);
 
 		if (dr6 != 0) {
-			vcpu->arch.dr6 &= ~DR_TRAP_BITS;
-			vcpu->arch.dr6 |= dr6 | DR6_RTM;
-			kvm_queue_exception(vcpu, DB_VECTOR);
+			kvm_queue_exception_p(vcpu, DB_VECTOR, dr6);
 			*r = 1;
 			return true;
 		}
@@ -8042,7 +8047,7 @@ void kvm_make_scan_ioapic_request_mask(struct kvm *kvm,
 	zalloc_cpumask_var(&cpus, GFP_ATOMIC);
 
 	kvm_make_vcpus_request_mask(kvm, KVM_REQ_SCAN_IOAPIC,
-				    vcpu_bitmap, cpus);
+				    NULL, vcpu_bitmap, cpus);
 
 	free_cpumask_var(cpus);
 }
@@ -8072,6 +8077,7 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_update_apicv);
  */
 void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
 {
+	struct kvm_vcpu *except;
 	unsigned long old, new, expected;
 
 	if (!kvm_x86_ops.check_apicv_inhibit_reasons ||
@@ -8096,7 +8102,17 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
 	trace_kvm_apicv_update_request(activate, bit);
 	if (kvm_x86_ops.pre_update_apicv_exec_ctrl)
 		kvm_x86_ops.pre_update_apicv_exec_ctrl(kvm, activate);
-	kvm_make_all_cpus_request(kvm, KVM_REQ_APICV_UPDATE);
+
+	/*
+	 * Sending request to update APICV for all other vcpus,
+	 * while update the calling vcpu immediately instead of
+	 * waiting for another #VMEXIT to handle the request.
+	 */
+	except = kvm_get_running_vcpu();
+	kvm_make_all_cpus_request_except(kvm, KVM_REQ_APICV_UPDATE,
+					 except);
+	if (except)
+		kvm_vcpu_update_apicv(except);
 }
 EXPORT_SYMBOL_GPL(kvm_request_apicv_update);
 
@@ -8420,7 +8436,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		WARN_ON(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP);
 		kvm_x86_ops.sync_dirty_debug_regs(vcpu);
 		kvm_update_dr0123(vcpu);
-		kvm_update_dr6(vcpu);
 		kvm_update_dr7(vcpu);
 		vcpu->arch.switch_db_regs &= ~KVM_DEBUGREG_RELOAD;
 	}
@@ -9481,7 +9496,6 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
 	memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
 	kvm_update_dr0123(vcpu);
 	vcpu->arch.dr6 = DR6_INIT;
-	kvm_update_dr6(vcpu);
 	vcpu->arch.dr7 = DR7_FIXED_1;
 	kvm_update_dr7(vcpu);
 
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 01276e3d01b9..131cc1527d68 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -813,8 +813,11 @@ void kvm_flush_remote_tlbs(struct kvm *kvm);
 void kvm_reload_remote_mmus(struct kvm *kvm);
 
 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
+				 struct kvm_vcpu *except,
 				 unsigned long *vcpu_bitmap, cpumask_var_t tmp);
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req);
+bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
+				      struct kvm_vcpu *except);
 bool kvm_make_cpus_request_mask(struct kvm *kvm, unsigned int req,
 				unsigned long *vcpu_bitmap);
 
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index b728c0a0f9b2..42f4f49f2a48 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -54,6 +54,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
 TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
+TEST_GEN_PROGS_x86_64 += x86_64/debug_regs
 TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
 TEST_GEN_PROGS_x86_64 += demand_paging_test
 TEST_GEN_PROGS_x86_64 += dirty_log_test
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index a99b875f50d2..92e184a422ee 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -143,6 +143,8 @@ struct kvm_run *vcpu_state(struct kvm_vm *vm, uint32_t vcpuid);
 void vcpu_run(struct kvm_vm *vm, uint32_t vcpuid);
 int _vcpu_run(struct kvm_vm *vm, uint32_t vcpuid);
 void vcpu_run_complete_io(struct kvm_vm *vm, uint32_t vcpuid);
+void vcpu_set_guest_debug(struct kvm_vm *vm, uint32_t vcpuid,
+			  struct kvm_guest_debug *debug);
 void vcpu_set_mp_state(struct kvm_vm *vm, uint32_t vcpuid,
 		       struct kvm_mp_state *mp_state);
 void vcpu_regs_get(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_regs *regs);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 8a3523d4434f..9622431069bc 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -1201,6 +1201,15 @@ void vcpu_run_complete_io(struct kvm_vm *vm, uint32_t vcpuid)
 		    ret, errno);
 }
 
+void vcpu_set_guest_debug(struct kvm_vm *vm, uint32_t vcpuid,
+			  struct kvm_guest_debug *debug)
+{
+	struct vcpu *vcpu = vcpu_find(vm, vcpuid);
+	int ret = ioctl(vcpu->fd, KVM_SET_GUEST_DEBUG, debug);
+
+	TEST_ASSERT(ret == 0, "KVM_SET_GUEST_DEBUG failed: %d", ret);
+}
+
 /*
  * VM VCPU Set MP State
  *
diff --git a/tools/testing/selftests/kvm/x86_64/debug_regs.c b/tools/testing/selftests/kvm/x86_64/debug_regs.c
new file mode 100644
index 000000000000..8162c58a1234
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/debug_regs.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM guest debug register tests
+ *
+ * Copyright (C) 2020, Red Hat, Inc.
+ */
+#include <stdio.h>
+#include <string.h>
+#include "kvm_util.h"
+#include "processor.h"
+
+#define VCPU_ID 0
+
+#define DR6_BD		(1 << 13)
+#define DR7_GD		(1 << 13)
+
+/* For testing data access debug BP */
+uint32_t guest_value;
+
+extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;
+
+static void guest_code(void)
+{
+	/*
+	 * Software BP tests.
+	 *
+	 * NOTE: sw_bp need to be before the cmd here, because int3 is an
+	 * exception rather than a normal trap for KVM_SET_GUEST_DEBUG (we
+	 * capture it using the vcpu exception bitmap).
+	 */
+	asm volatile("sw_bp: int3");
+
+	/* Hardware instruction BP test */
+	asm volatile("hw_bp: nop");
+
+	/* Hardware data BP test */
+	asm volatile("mov $1234,%%rax;\n\t"
+		     "mov %%rax,%0;\n\t write_data:"
+		     : "=m" (guest_value) : : "rax");
+
+	/* Single step test, covers 2 basic instructions and 2 emulated */
+	asm volatile("ss_start: "
+		     "xor %%rax,%%rax\n\t"
+		     "cpuid\n\t"
+		     "movl $0x1a0,%%ecx\n\t"
+		     "rdmsr\n\t"
+		     : : : "rax", "ecx");
+
+	/* DR6.BD test */
+	asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");
+	GUEST_DONE();
+}
+
+#define  CLEAR_DEBUG()  memset(&debug, 0, sizeof(debug))
+#define  APPLY_DEBUG()  vcpu_set_guest_debug(vm, VCPU_ID, &debug)
+#define  CAST_TO_RIP(v)  ((unsigned long long)&(v))
+#define  SET_RIP(v)  do {				\
+		vcpu_regs_get(vm, VCPU_ID, &regs);	\
+		regs.rip = (v);				\
+		vcpu_regs_set(vm, VCPU_ID, &regs);	\
+	} while (0)
+#define  MOVE_RIP(v)  SET_RIP(regs.rip + (v));
+
+int main(void)
+{
+	struct kvm_guest_debug debug;
+	unsigned long long target_dr6, target_rip;
+	struct kvm_regs regs;
+	struct kvm_run *run;
+	struct kvm_vm *vm;
+	struct ucall uc;
+	uint64_t cmd;
+	int i;
+	/* Instruction lengths starting at ss_start */
+	int ss_size[4] = {
+		3,		/* xor */
+		2,		/* cpuid */
+		5,		/* mov */
+		2,		/* rdmsr */
+	};
+
+	if (!kvm_check_cap(KVM_CAP_SET_GUEST_DEBUG)) {
+		print_skip("KVM_CAP_SET_GUEST_DEBUG not supported");
+		return 0;
+	}
+
+	vm = vm_create_default(VCPU_ID, 0, guest_code);
+	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
+	run = vcpu_state(vm, VCPU_ID);
+
+	/* Test software BPs - int3 */
+	CLEAR_DEBUG();
+	debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
+	APPLY_DEBUG();
+	vcpu_run(vm, VCPU_ID);
+	TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+		    run->debug.arch.exception == BP_VECTOR &&
+		    run->debug.arch.pc == CAST_TO_RIP(sw_bp),
+		    "INT3: exit %d exception %d rip 0x%llx (should be 0x%llx)",
+		    run->exit_reason, run->debug.arch.exception,
+		    run->debug.arch.pc, CAST_TO_RIP(sw_bp));
+	MOVE_RIP(1);
+
+	/* Test instruction HW BP over DR[0-3] */
+	for (i = 0; i < 4; i++) {
+		CLEAR_DEBUG();
+		debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
+		debug.arch.debugreg[i] = CAST_TO_RIP(hw_bp);
+		debug.arch.debugreg[7] = 0x400 | (1UL << (2*i+1));
+		APPLY_DEBUG();
+		vcpu_run(vm, VCPU_ID);
+		target_dr6 = 0xffff0ff0 | (1UL << i);
+		TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+			    run->debug.arch.exception == DB_VECTOR &&
+			    run->debug.arch.pc == CAST_TO_RIP(hw_bp) &&
+			    run->debug.arch.dr6 == target_dr6,
+			    "INS_HW_BP (DR%d): exit %d exception %d rip 0x%llx "
+			    "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
+			    i, run->exit_reason, run->debug.arch.exception,
+			    run->debug.arch.pc, CAST_TO_RIP(hw_bp),
+			    run->debug.arch.dr6, target_dr6);
+	}
+	/* Skip "nop" */
+	MOVE_RIP(1);
+
+	/* Test data access HW BP over DR[0-3] */
+	for (i = 0; i < 4; i++) {
+		CLEAR_DEBUG();
+		debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
+		debug.arch.debugreg[i] = CAST_TO_RIP(guest_value);
+		debug.arch.debugreg[7] = 0x00000400 | (1UL << (2*i+1)) |
+		    (0x000d0000UL << (4*i));
+		APPLY_DEBUG();
+		vcpu_run(vm, VCPU_ID);
+		target_dr6 = 0xffff0ff0 | (1UL << i);
+		TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+			    run->debug.arch.exception == DB_VECTOR &&
+			    run->debug.arch.pc == CAST_TO_RIP(write_data) &&
+			    run->debug.arch.dr6 == target_dr6,
+			    "DATA_HW_BP (DR%d): exit %d exception %d rip 0x%llx "
+			    "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
+			    i, run->exit_reason, run->debug.arch.exception,
+			    run->debug.arch.pc, CAST_TO_RIP(write_data),
+			    run->debug.arch.dr6, target_dr6);
+		/* Rollback the 4-bytes "mov" */
+		MOVE_RIP(-7);
+	}
+	/* Skip the 4-bytes "mov" */
+	MOVE_RIP(7);
+
+	/* Test single step */
+	target_rip = CAST_TO_RIP(ss_start);
+	target_dr6 = 0xffff4ff0ULL;
+	vcpu_regs_get(vm, VCPU_ID, &regs);
+	for (i = 0; i < (sizeof(ss_size) / sizeof(ss_size[0])); i++) {
+		target_rip += ss_size[i];
+		CLEAR_DEBUG();
+		debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
+		debug.arch.debugreg[7] = 0x00000400;
+		APPLY_DEBUG();
+		vcpu_run(vm, VCPU_ID);
+		TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+			    run->debug.arch.exception == DB_VECTOR &&
+			    run->debug.arch.pc == target_rip &&
+			    run->debug.arch.dr6 == target_dr6,
+			    "SINGLE_STEP[%d]: exit %d exception %d rip 0x%llx "
+			    "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
+			    i, run->exit_reason, run->debug.arch.exception,
+			    run->debug.arch.pc, target_rip, run->debug.arch.dr6,
+			    target_dr6);
+	}
+
+	/* Finally test global disable */
+	CLEAR_DEBUG();
+	debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
+	debug.arch.debugreg[7] = 0x400 | DR7_GD;
+	APPLY_DEBUG();
+	vcpu_run(vm, VCPU_ID);
+	target_dr6 = 0xffff0ff0 | DR6_BD;
+	TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+		    run->debug.arch.exception == DB_VECTOR &&
+		    run->debug.arch.pc == CAST_TO_RIP(bd_start) &&
+		    run->debug.arch.dr6 == target_dr6,
+			    "DR7.GD: exit %d exception %d rip 0x%llx "
+			    "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
+			    run->exit_reason, run->debug.arch.exception,
+			    run->debug.arch.pc, target_rip, run->debug.arch.dr6,
+			    target_dr6);
+
+	/* Disable all debug controls, run to the end */
+	CLEAR_DEBUG();
+	APPLY_DEBUG();
+
+	vcpu_run(vm, VCPU_ID);
+	TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, "KVM_EXIT_IO");
+	cmd = get_ucall(vm, VCPU_ID, &uc);
+	TEST_ASSERT(cmd == UCALL_DONE, "UCALL_DONE");
+
+	kvm_vm_free(vm);
+
+	return 0;
+}
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 74bdb7bf3295..731c1e517716 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -259,6 +259,7 @@ static inline bool kvm_kick_many_cpus(const struct cpumask *cpus, bool wait)
 }
 
 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
+				 struct kvm_vcpu *except,
 				 unsigned long *vcpu_bitmap, cpumask_var_t tmp)
 {
 	int i, cpu, me;
@@ -268,7 +269,8 @@ bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
 	me = get_cpu();
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
-		if (vcpu_bitmap && !test_bit(i, vcpu_bitmap))
+		if ((vcpu_bitmap && !test_bit(i, vcpu_bitmap)) ||
+		    vcpu == except)
 			continue;
 
 		kvm_make_request(req, vcpu);
@@ -288,19 +290,25 @@ bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
 	return called;
 }
 
-bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
+bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
+				      struct kvm_vcpu *except)
 {
 	cpumask_var_t cpus;
 	bool called;
 
 	zalloc_cpumask_var(&cpus, GFP_ATOMIC);
 
-	called = kvm_make_vcpus_request_mask(kvm, req, NULL, cpus);
+	called = kvm_make_vcpus_request_mask(kvm, req, except, NULL, cpus);
 
 	free_cpumask_var(cpus);
 	return called;
 }
 
+bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
+{
+	return kvm_make_all_cpus_request_except(kvm, req, NULL);
+}
+
 #ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
 void kvm_flush_remote_tlbs(struct kvm *kvm)
 {