From 85c856b39b479dde410ddd09df1da745343010c9 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Wed, 26 Oct 2016 08:38:38 -0700 Subject: kvm: nVMX: Fix kernel panics induced by illegal INVEPT/INVVPID types Bitwise shifts by amounts greater than or equal to the width of the left operand are undefined. A malicious guest can exploit this to crash a 32-bit host, due to the BUG_ON(1)'s in handle_{invept,invvpid}. Signed-off-by: Jim Mattson Message-Id: <1477496318-17681-1-git-send-email-jmattson@google.com> [Change 1UL to 1, to match the range check on the shift count. - Paolo] Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index cf1b16dbc98a..74a4df993a51 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -7659,7 +7659,7 @@ static int handle_invept(struct kvm_vcpu *vcpu) types = (vmx->nested.nested_vmx_ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6; - if (!(types & (1UL << type))) { + if (type >= 32 || !(types & (1 << type))) { nested_vmx_failValid(vcpu, VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID); skip_emulated_instruction(vcpu); @@ -7722,7 +7722,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu) types = (vmx->nested.nested_vmx_vpid_caps >> 8) & 0x7; - if (!(types & (1UL << type))) { + if (type >= 32 || !(types & (1 << type))) { nested_vmx_failValid(vcpu, VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID); skip_emulated_instruction(vcpu); -- cgit v1.2.3 From 796f4687bd622b0f8076b6695001ab5cdc2b722a Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 27 Oct 2016 20:14:45 +0200 Subject: kvm/x86: Show WRMSR data is in hex MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add the "0x" prefix to the error messages format to make it unambiguous about what kind of value we're talking about. Signed-off-by: Borislav Petkov Cc: Paolo Bonzini Cc: "Radim Krčmář" Message-Id: <20161027181445.25319-1-bp@alien8.de> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e375235d81c9..0b2087981c06 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2262,7 +2262,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) /* Drop writes to this legacy MSR -- see rdmsr * counterpart for further detail. */ - vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data %llx\n", msr, data); + vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n", msr, data); break; case MSR_AMD64_OSVW_ID_LENGTH: if (!guest_cpuid_has_osvw(vcpu)) @@ -2280,11 +2280,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (kvm_pmu_is_valid_msr(vcpu, msr)) return kvm_pmu_set_msr(vcpu, msr_info); if (!ignore_msrs) { - vcpu_unimpl(vcpu, "unhandled wrmsr: 0x%x data %llx\n", + vcpu_unimpl(vcpu, "unhandled wrmsr: 0x%x data 0x%llx\n", msr, data); return 1; } else { - vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data %llx\n", + vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n", msr, data); break; } -- cgit v1.2.3 From bd768e146624cbec7122ed15dead8daa137d909d Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Fri, 21 Oct 2016 12:39:57 -0400 Subject: KVM: x86: fix wbinvd_dirty_mask use-after-free MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit vcpu->arch.wbinvd_dirty_mask may still be used after freeing it, corrupting memory. For example, the following call trace may set a bit in an already freed cpu mask: kvm_arch_vcpu_load vcpu_load vmx_free_vcpu_nested vmx_free_vcpu kvm_arch_vcpu_free Fix this by deferring freeing of wbinvd_dirty_mask. Cc: stable@vger.kernel.org Signed-off-by: Ido Yariv Reviewed-by: Paolo Bonzini Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0b2087981c06..e954be8a3185 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7410,10 +7410,12 @@ void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu) { + void *wbinvd_dirty_mask = vcpu->arch.wbinvd_dirty_mask; + kvmclock_reset(vcpu); - free_cpumask_var(vcpu->arch.wbinvd_dirty_mask); kvm_x86_ops->vcpu_free(vcpu); + free_cpumask_var(wbinvd_dirty_mask); } struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, -- cgit v1.2.3 From ea26e4ec08d4727e3a9e48a6b74695861effcbd9 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 1 Nov 2016 00:39:48 +0100 Subject: KVM: x86: drop TSC offsetting kvm_x86_ops to fix KVM_GET/SET_CLOCK MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since commit a545ab6a0085 ("kvm: x86: add tsc_offset field to struct kvm_vcpu_arch", 2016-09-07) the offset between host and L1 TSC is cached and need not be fished out of the VMCS or VMCB. This means that we can implement adjust_tsc_offset_guest and read_l1_tsc entirely in generic code. The simplification is particularly significant for VMX code, where vmx->nested.vmcs01_tsc_offset was duplicating what is now in vcpu->arch.tsc_offset. Therefore the vmcs01_tsc_offset can be dropped completely. More importantly, this fixes KVM_GET_CLOCK/KVM_SET_CLOCK which, after commit 108b249c453d ("KVM: x86: introduce get_kvmclock_ns", 2016-09-01) called read_l1_tsc while the VMCS was not loaded. It thus returned bogus values on Intel CPUs. Fixes: 108b249c453dd7132599ab6dc7e435a7036c193f Reported-by: Roman Kagan Reviewed-by: Radim Krčmář Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 23 ----------------------- arch/x86/kvm/vmx.c | 39 +++------------------------------------ arch/x86/kvm/x86.c | 6 +++--- 3 files changed, 6 insertions(+), 62 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index f8157a36ab09..8ca1eca5038d 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1138,21 +1138,6 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) mark_dirty(svm->vmcb, VMCB_INTERCEPTS); } -static void svm_adjust_tsc_offset_guest(struct kvm_vcpu *vcpu, s64 adjustment) -{ - struct vcpu_svm *svm = to_svm(vcpu); - - svm->vmcb->control.tsc_offset += adjustment; - if (is_guest_mode(vcpu)) - svm->nested.hsave->control.tsc_offset += adjustment; - else - trace_kvm_write_tsc_offset(vcpu->vcpu_id, - svm->vmcb->control.tsc_offset - adjustment, - svm->vmcb->control.tsc_offset); - - mark_dirty(svm->vmcb, VMCB_INTERCEPTS); -} - static void avic_init_vmcb(struct vcpu_svm *svm) { struct vmcb *vmcb = svm->vmcb; @@ -3449,12 +3434,6 @@ static int cr8_write_interception(struct vcpu_svm *svm) return 0; } -static u64 svm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc) -{ - struct vmcb *vmcb = get_host_vmcb(to_svm(vcpu)); - return vmcb->control.tsc_offset + host_tsc; -} - static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { struct vcpu_svm *svm = to_svm(vcpu); @@ -5422,8 +5401,6 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = { .has_wbinvd_exit = svm_has_wbinvd_exit, .write_tsc_offset = svm_write_tsc_offset, - .adjust_tsc_offset_guest = svm_adjust_tsc_offset_guest, - .read_l1_tsc = svm_read_l1_tsc, .set_tdp_cr3 = set_tdp_cr3, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 74a4df993a51..754c3a7f444a 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -421,7 +421,6 @@ struct nested_vmx { /* vmcs02_list cache of VMCSs recently used to run L2 guests */ struct list_head vmcs02_pool; int vmcs02_num; - u64 vmcs01_tsc_offset; bool change_vmcs01_virtual_x2apic_mode; /* L2 must run next, and mustn't decide to exit to L1. */ bool nested_run_pending; @@ -2604,20 +2603,6 @@ static u64 guest_read_tsc(struct kvm_vcpu *vcpu) return kvm_scale_tsc(vcpu, host_tsc) + tsc_offset; } -/* - * Like guest_read_tsc, but always returns L1's notion of the timestamp - * counter, even if a nested guest (L2) is currently running. - */ -static u64 vmx_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc) -{ - u64 tsc_offset; - - tsc_offset = is_guest_mode(vcpu) ? - to_vmx(vcpu)->nested.vmcs01_tsc_offset : - vmcs_read64(TSC_OFFSET); - return host_tsc + tsc_offset; -} - /* * writes 'offset' into guest's timestamp counter offset register */ @@ -2631,7 +2616,6 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) * to the newly set TSC to get L2's TSC. */ struct vmcs12 *vmcs12; - to_vmx(vcpu)->nested.vmcs01_tsc_offset = offset; /* recalculate vmcs02.TSC_OFFSET: */ vmcs12 = get_vmcs12(vcpu); vmcs_write64(TSC_OFFSET, offset + @@ -2644,19 +2628,6 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) } } -static void vmx_adjust_tsc_offset_guest(struct kvm_vcpu *vcpu, s64 adjustment) -{ - u64 offset = vmcs_read64(TSC_OFFSET); - - vmcs_write64(TSC_OFFSET, offset + adjustment); - if (is_guest_mode(vcpu)) { - /* Even when running L2, the adjustment needs to apply to L1 */ - to_vmx(vcpu)->nested.vmcs01_tsc_offset += adjustment; - } else - trace_kvm_write_tsc_offset(vcpu->vcpu_id, offset, - offset + adjustment); -} - static bool guest_cpuid_has_vmx(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best = kvm_find_cpuid_entry(vcpu, 1, 0); @@ -10061,9 +10032,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING) vmcs_write64(TSC_OFFSET, - vmx->nested.vmcs01_tsc_offset + vmcs12->tsc_offset); + vcpu->arch.tsc_offset + vmcs12->tsc_offset); else - vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset); + vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset); if (kvm_has_tsc_control) decache_tsc_multiplier(vmx); @@ -10293,8 +10264,6 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) enter_guest_mode(vcpu); - vmx->nested.vmcs01_tsc_offset = vmcs_read64(TSC_OFFSET); - if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); @@ -10818,7 +10787,7 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, load_vmcs12_host_state(vcpu, vmcs12); /* Update any VMCS fields that might have changed while L2 ran */ - vmcs_write64(TSC_OFFSET, vmx->nested.vmcs01_tsc_offset); + vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset); if (vmx->hv_deadline_tsc == -1) vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL, PIN_BASED_VMX_PREEMPTION_TIMER); @@ -11339,8 +11308,6 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { .has_wbinvd_exit = cpu_has_vmx_wbinvd_exit, .write_tsc_offset = vmx_write_tsc_offset, - .adjust_tsc_offset_guest = vmx_adjust_tsc_offset_guest, - .read_l1_tsc = vmx_read_l1_tsc, .set_tdp_cr3 = vmx_set_cr3, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e954be8a3185..3017de0431bd 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1409,7 +1409,7 @@ static u64 kvm_compute_tsc_offset(struct kvm_vcpu *vcpu, u64 target_tsc) u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc) { - return kvm_x86_ops->read_l1_tsc(vcpu, kvm_scale_tsc(vcpu, host_tsc)); + return vcpu->arch.tsc_offset + kvm_scale_tsc(vcpu, host_tsc); } EXPORT_SYMBOL_GPL(kvm_read_l1_tsc); @@ -1547,7 +1547,7 @@ EXPORT_SYMBOL_GPL(kvm_write_tsc); static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu, s64 adjustment) { - kvm_x86_ops->adjust_tsc_offset_guest(vcpu, adjustment); + kvm_vcpu_write_tsc_offset(vcpu, vcpu->arch.tsc_offset + adjustment); } static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment) @@ -1555,7 +1555,7 @@ static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment) if (vcpu->arch.tsc_scaling_ratio != kvm_default_tsc_scaling_ratio) WARN_ON(adjustment < 0); adjustment = kvm_scale_tsc(vcpu, (u64) adjustment); - kvm_x86_ops->adjust_tsc_offset_guest(vcpu, adjustment); + adjust_tsc_offset_guest(vcpu, adjustment); } #ifdef CONFIG_X86_64 -- cgit v1.2.3 From 355f4fb1405ec29d0fac49b4d41fcd78cbd455d5 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Fri, 28 Oct 2016 08:29:39 -0700 Subject: kvm: nVMX: VMCLEAR an active shadow VMCS after last use After a successful VM-entry with the "VMCS shadowing" VM-execution control set, the shadow VMCS referenced by the VMCS link pointer field in the current VMCS becomes active on the logical processor. A VMCS that is made active on more than one logical processor may become corrupted. Therefore, before an active VMCS can be migrated to another logical processor, the first logical processor must execute a VMCLEAR for the active VMCS. VMCLEAR both ensures that all VMCS data are written to memory and makes the VMCS inactive. Signed-off-by: Jim Mattson Reviewed-By: David Matlack Message-Id: <1477668579-22555-1-git-send-email-jmattson@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 754c3a7f444a..5382b82462fc 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -187,6 +187,7 @@ struct vmcs { */ struct loaded_vmcs { struct vmcs *vmcs; + struct vmcs *shadow_vmcs; int cpu; int launched; struct list_head loaded_vmcss_on_cpu_link; @@ -411,7 +412,6 @@ struct nested_vmx { * memory during VMXOFF, VMCLEAR, VMPTRLD. */ struct vmcs12 *cached_vmcs12; - struct vmcs *current_shadow_vmcs; /* * Indicates if the shadow vmcs must be updated with the * data hold by vmcs12 @@ -1418,6 +1418,8 @@ static void vmcs_clear(struct vmcs *vmcs) static inline void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs) { vmcs_clear(loaded_vmcs->vmcs); + if (loaded_vmcs->shadow_vmcs && loaded_vmcs->launched) + vmcs_clear(loaded_vmcs->shadow_vmcs); loaded_vmcs->cpu = -1; loaded_vmcs->launched = 0; } @@ -3533,6 +3535,7 @@ static void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) loaded_vmcs_clear(loaded_vmcs); free_vmcs(loaded_vmcs->vmcs); loaded_vmcs->vmcs = NULL; + WARN_ON(loaded_vmcs->shadow_vmcs != NULL); } static void free_kvm_area(void) @@ -6667,6 +6670,7 @@ static struct loaded_vmcs *nested_get_current_vmcs02(struct vcpu_vmx *vmx) if (!item) return NULL; item->vmcs02.vmcs = alloc_vmcs(); + item->vmcs02.shadow_vmcs = NULL; if (!item->vmcs02.vmcs) { kfree(item); return NULL; @@ -7043,7 +7047,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu) shadow_vmcs->revision_id |= (1u << 31); /* init shadow vmcs */ vmcs_clear(shadow_vmcs); - vmx->nested.current_shadow_vmcs = shadow_vmcs; + vmx->vmcs01.shadow_vmcs = shadow_vmcs; } INIT_LIST_HEAD(&(vmx->nested.vmcs02_pool)); @@ -7145,8 +7149,11 @@ static void free_nested(struct vcpu_vmx *vmx) free_page((unsigned long)vmx->nested.msr_bitmap); vmx->nested.msr_bitmap = NULL; } - if (enable_shadow_vmcs) - free_vmcs(vmx->nested.current_shadow_vmcs); + if (enable_shadow_vmcs) { + vmcs_clear(vmx->vmcs01.shadow_vmcs); + free_vmcs(vmx->vmcs01.shadow_vmcs); + vmx->vmcs01.shadow_vmcs = NULL; + } kfree(vmx->nested.cached_vmcs12); /* Unpin physical memory we referred to in current vmcs02 */ if (vmx->nested.apic_access_page) { @@ -7323,7 +7330,7 @@ static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx) int i; unsigned long field; u64 field_value; - struct vmcs *shadow_vmcs = vmx->nested.current_shadow_vmcs; + struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs; const unsigned long *fields = shadow_read_write_fields; const int num_fields = max_shadow_read_write_fields; @@ -7372,7 +7379,7 @@ static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx) int i, q; unsigned long field; u64 field_value = 0; - struct vmcs *shadow_vmcs = vmx->nested.current_shadow_vmcs; + struct vmcs *shadow_vmcs = vmx->vmcs01.shadow_vmcs; vmcs_load(shadow_vmcs); @@ -7562,7 +7569,7 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu) vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_SHADOW_VMCS); vmcs_write64(VMCS_LINK_POINTER, - __pa(vmx->nested.current_shadow_vmcs)); + __pa(vmx->vmcs01.shadow_vmcs)); vmx->nested.sync_shadow_vmcs = true; } } @@ -9127,6 +9134,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) vmx->loaded_vmcs = &vmx->vmcs01; vmx->loaded_vmcs->vmcs = alloc_vmcs(); + vmx->loaded_vmcs->shadow_vmcs = NULL; if (!vmx->loaded_vmcs->vmcs) goto free_msrs; if (!vmm_exclusive) -- cgit v1.2.3 From d9092f52d7e61dd1557f2db2400ddb430e85937e Mon Sep 17 00:00:00 2001 From: Owen Hofmann Date: Thu, 27 Oct 2016 11:25:52 -0700 Subject: kvm: x86: Check memopp before dereference (CVE-2016-8630) Commit 41061cdb98 ("KVM: emulate: do not initialize memopp") removes a check for non-NULL under incorrect assumptions. An undefined instruction with a ModR/M byte with Mod=0 and R/M-5 (e.g. 0xc7 0x15) will attempt to dereference a null pointer here. Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5 Message-Id: <1477592752-126650-2-git-send-email-osh@google.com> Signed-off-by: Owen Hofmann Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 4e95d3eb2955..cbd7b92585bb 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5045,7 +5045,7 @@ done_prefixes: /* Decode and fetch the destination operand: register or memory. */ rc = decode_operand(ctxt, &ctxt->dst, (ctxt->d >> DstShift) & OpMask); - if (ctxt->rip_relative) + if (ctxt->rip_relative && likely(ctxt->memopp)) ctxt->memopp->addr.mem.ea = address_mask(ctxt, ctxt->memopp->addr.mem.ea + ctxt->_eip); -- cgit v1.2.3 From 8b9534406456313beb7bf9051150b50c63049ab7 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 16 Nov 2016 18:31:30 +0100 Subject: KVM: x86: do not go through vcpu in __get_kvmclock_ns MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Going through the first VCPU is wrong if you follow a KVM_SET_CLOCK with a KVM_GET_CLOCK immediately after, without letting the VCPU run and call kvm_guest_time_update. To fix this, compute the kvmclock value ourselves, using the master clock (tsc, nsec) pair as the base and the host CPU frequency as the scale. Reported-by: Marcelo Tosatti Signed-off-by: Paolo Bonzini Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3017de0431bd..7d3d9d4d6124 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1724,18 +1724,23 @@ static void kvm_gen_update_masterclock(struct kvm *kvm) static u64 __get_kvmclock_ns(struct kvm *kvm) { - struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, 0); struct kvm_arch *ka = &kvm->arch; - s64 ns; + struct pvclock_vcpu_time_info hv_clock; - if (vcpu->arch.hv_clock.flags & PVCLOCK_TSC_STABLE_BIT) { - u64 tsc = kvm_read_l1_tsc(vcpu, rdtsc()); - ns = __pvclock_read_cycles(&vcpu->arch.hv_clock, tsc); - } else { - ns = ktime_get_boot_ns() + ka->kvmclock_offset; + spin_lock(&ka->pvclock_gtod_sync_lock); + if (!ka->use_master_clock) { + spin_unlock(&ka->pvclock_gtod_sync_lock); + return ktime_get_boot_ns() + ka->kvmclock_offset; } - return ns; + hv_clock.tsc_timestamp = ka->master_cycle_now; + hv_clock.system_time = ka->master_kernel_ns + ka->kvmclock_offset; + spin_unlock(&ka->pvclock_gtod_sync_lock); + + kvm_get_time_scale(NSEC_PER_SEC, __this_cpu_read(cpu_tsc_khz) * 1000LL, + &hv_clock.tsc_shift, + &hv_clock.tsc_to_system_mul); + return __pvclock_read_cycles(&hv_clock, rdtsc()); } u64 get_kvmclock_ns(struct kvm *kvm) -- cgit v1.2.3 From 1650b4ebc99da4c137bfbfc531be4a2405f951dd Mon Sep 17 00:00:00 2001 From: Ignacio Alvarado Date: Fri, 4 Nov 2016 12:15:55 -0700 Subject: KVM: Disable irq while unregistering user notifier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Function user_notifier_unregister should be called only once for each registered user notifier. Function kvm_arch_hardware_disable can be executed from an IPI context which could cause a race condition with a VCPU returning to user mode and attempting to unregister the notifier. Signed-off-by: Ignacio Alvarado Cc: stable@vger.kernel.org Fixes: 18863bdd60f8 ("KVM: x86 shared msr infrastructure") Reviewed-by: Paolo Bonzini Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7d3d9d4d6124..2f27af4f312a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -210,7 +210,18 @@ static void kvm_on_user_return(struct user_return_notifier *urn) struct kvm_shared_msrs *locals = container_of(urn, struct kvm_shared_msrs, urn); struct kvm_shared_msr_values *values; + unsigned long flags; + /* + * Disabling irqs at this point since the following code could be + * interrupted and executed through kvm_arch_hardware_disable() + */ + local_irq_save(flags); + if (locals->registered) { + locals->registered = false; + user_return_notifier_unregister(urn); + } + local_irq_restore(flags); for (slot = 0; slot < shared_msrs_global.nr; ++slot) { values = &locals->values[slot]; if (values->host != values->curr) { @@ -218,8 +229,6 @@ static void kvm_on_user_return(struct user_return_notifier *urn) values->curr = values->host; } } - locals->registered = false; - user_return_notifier_unregister(urn); } static void shared_msr_update(unsigned slot, u32 msr) -- cgit v1.2.3 From e3fd9a93a12a1020067a676e826877623cee8e2b Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 9 Nov 2016 17:48:15 +0100 Subject: kvm: kvmclock: let KVM_GET_CLOCK return whether the master clock is in use MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Userspace can read the exact value of kvmclock by reading the TSC and fetching the timekeeping parameters out of guest memory. This however is brittle and not necessary anymore with KVM 4.11. Provide a mechanism that lets userspace know if the new KVM_GET_CLOCK semantics are in effect, and---since we are at it---if the clock is stable across all VCPUs. Cc: Radim Krčmář Cc: Marcelo Tosatti Signed-off-by: Paolo Bonzini Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2f27af4f312a..3320804bb2ac 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2610,7 +2610,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_PIT_STATE2: case KVM_CAP_SET_IDENTITY_MAP_ADDR: case KVM_CAP_XEN_HVM: - case KVM_CAP_ADJUST_CLOCK: case KVM_CAP_VCPU_EVENTS: case KVM_CAP_HYPERV: case KVM_CAP_HYPERV_VAPIC: @@ -2637,6 +2636,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) #endif r = 1; break; + case KVM_CAP_ADJUST_CLOCK: + r = KVM_CLOCK_TSC_STABLE; + break; case KVM_CAP_X86_SMM: /* SMBASE is usually relocated above 1M on modern chipsets, * and SMM handlers might indeed rely on 4G segment limits, @@ -4117,9 +4119,11 @@ long kvm_arch_vm_ioctl(struct file *filp, struct kvm_clock_data user_ns; u64 now_ns; - now_ns = get_kvmclock_ns(kvm); + local_irq_disable(); + now_ns = __get_kvmclock_ns(kvm); user_ns.clock = now_ns; - user_ns.flags = 0; + user_ns.flags = kvm->arch.use_master_clock ? KVM_CLOCK_TSC_STABLE : 0; + local_irq_enable(); memset(&user_ns.pad, 0, sizeof(user_ns.pad)); r = -EFAULT; -- cgit v1.2.3 From 7301d6abaea926d685832f7e1f0c37dd206b01f4 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 17 Nov 2016 15:55:46 +0100 Subject: KVM: x86: fix missed SRCU usage in kvm_lapic_set_vapic_addr MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Reported by syzkaller: [ INFO: suspicious RCU usage. ] 4.9.0-rc4+ #47 Not tainted ------------------------------- ./include/linux/kvm_host.h:536 suspicious rcu_dereference_check() usage! stack backtrace: CPU: 1 PID: 6679 Comm: syz-executor Not tainted 4.9.0-rc4+ #47 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 ffff880039e2f6d0 ffffffff81c2e46b ffff88003e3a5b40 0000000000000000 0000000000000001 ffffffff83215600 ffff880039e2f700 ffffffff81334ea9 ffffc9000730b000 0000000000000004 ffff88003c4f8420 ffff88003d3f8000 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [] dump_stack+0xb3/0x118 lib/dump_stack.c:51 [] lockdep_rcu_suspicious+0x139/0x180 kernel/locking/lockdep.c:4445 [< inline >] __kvm_memslots include/linux/kvm_host.h:534 [< inline >] kvm_memslots include/linux/kvm_host.h:541 [] kvm_gfn_to_hva_cache_init+0xa1e/0xce0 virt/kvm/kvm_main.c:1941 [] kvm_lapic_set_vapic_addr+0xed/0x140 arch/x86/kvm/lapic.c:2217 Reported-by: Dmitry Vyukov Fixes: fda4e2e85589191b123d31cdc21fd33ee70f50fd Cc: Andrew Honig Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini Reviewed-by: David Hildenbrand Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3320804bb2ac..04c5d96b1d67 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3431,6 +3431,7 @@ long kvm_arch_vcpu_ioctl(struct file *filp, }; case KVM_SET_VAPIC_ADDR: { struct kvm_vapic_addr va; + int idx; r = -EINVAL; if (!lapic_in_kernel(vcpu)) @@ -3438,7 +3439,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, r = -EFAULT; if (copy_from_user(&va, argp, sizeof va)) goto out; + idx = srcu_read_lock(&vcpu->kvm->srcu); r = kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr); + srcu_read_unlock(&vcpu->kvm->srcu, idx); break; } case KVM_X86_SETUP_MCE: { -- cgit v1.2.3 From a2b07739ff5ded8ca7e9c7ff0749ed6f0d36aee2 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 17 Nov 2016 15:55:47 +0100 Subject: kvm: x86: merge kvm_arch_set_irq and kvm_arch_set_irq_inatomic MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit kvm_arch_set_irq is unused since commit b97e6de9c96. Merge its functionality with kvm_arch_set_irq_inatomic. Reported-by: Jiang Biao Signed-off-by: Paolo Bonzini Reviewed-by: David Hildenbrand Signed-off-by: Radim Krčmář --- arch/x86/kvm/irq_comm.c | 58 +++++++++++++++++++++++-------------------------- 1 file changed, 27 insertions(+), 31 deletions(-) (limited to 'arch/x86/kvm') diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c index 25810b144b58..4da03030d5a7 100644 --- a/arch/x86/kvm/irq_comm.c +++ b/arch/x86/kvm/irq_comm.c @@ -156,6 +156,16 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, } +static int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e, + struct kvm *kvm, int irq_source_id, int level, + bool line_status) +{ + if (!level) + return -1; + + return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint); +} + int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm, int irq_source_id, int level, bool line_status) @@ -163,18 +173,26 @@ int kvm_arch_set_irq_inatomic(struct kvm_kernel_irq_routing_entry *e, struct kvm_lapic_irq irq; int r; - if (unlikely(e->type != KVM_IRQ_ROUTING_MSI)) - return -EWOULDBLOCK; + switch (e->type) { + case KVM_IRQ_ROUTING_HV_SINT: + return kvm_hv_set_sint(e, kvm, irq_source_id, level, + line_status); - if (kvm_msi_route_invalid(kvm, e)) - return -EINVAL; + case KVM_IRQ_ROUTING_MSI: + if (kvm_msi_route_invalid(kvm, e)) + return -EINVAL; - kvm_set_msi_irq(kvm, e, &irq); + kvm_set_msi_irq(kvm, e, &irq); - if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r, NULL)) - return r; - else - return -EWOULDBLOCK; + if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r, NULL)) + return r; + break; + + default: + break; + } + + return -EWOULDBLOCK; } int kvm_request_irq_source_id(struct kvm *kvm) @@ -254,16 +272,6 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin, srcu_read_unlock(&kvm->irq_srcu, idx); } -static int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e, - struct kvm *kvm, int irq_source_id, int level, - bool line_status) -{ - if (!level) - return -1; - - return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint); -} - int kvm_set_routing_entry(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e, const struct kvm_irq_routing_entry *ue) @@ -423,18 +431,6 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, srcu_read_unlock(&kvm->irq_srcu, idx); } -int kvm_arch_set_irq(struct kvm_kernel_irq_routing_entry *irq, struct kvm *kvm, - int irq_source_id, int level, bool line_status) -{ - switch (irq->type) { - case KVM_IRQ_ROUTING_HV_SINT: - return kvm_hv_set_sint(irq, kvm, irq_source_id, level, - line_status); - default: - return -EWOULDBLOCK; - } -} - void kvm_arch_irq_routing_update(struct kvm *kvm) { kvm_hv_irq_routing_update(kvm); -- cgit v1.2.3