[PATCH AUTOSEL 4.19 011/167] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS

[PATCH AUTOSEL 4.19 011/167] KVM: x86: hyperv: enforce vp_index < KVM_MAX_VCPUS

[Sasha Levin]

From: Vitaly Kuznetsov <vkuznets@redhat.com>

[ Upstream commit 9170200ec0ebad70e5b9902bc93e2b1b11456a3b ]

Hyper-V TLFS (5.0b) states:

> Virtual processors are identified by using an index (VP index). The
> maximum number of virtual processors per partition supported by the
> current implementation of the hypervisor can be obtained through CPUID
> leaf 0x40000005. A virtual processor index must be less than the
> maximum number of virtual processors per partition.

Forbid userspace to set VP_INDEX above KVM_MAX_VCPUS. get_vcpu_by_vpidx()
can now be optimized to bail early when supplied vpidx is >= KVM_MAX_VCPUS.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/hyperv.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 229d996051653..73fa074b9089a 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -132,8 +132,10 @@ static struct kvm_vcpu *get_vcpu_by_vpidx(struct kvm *kvm, u32 vpidx)
 	struct kvm_vcpu *vcpu = NULL;
 	int i;
 
-	if (vpidx < KVM_MAX_VCPUS)
-		vcpu = kvm_get_vcpu(kvm, vpidx);
+	if (vpidx >= KVM_MAX_VCPUS)
+		return NULL;
+
+	vcpu = kvm_get_vcpu(kvm, vpidx);
 	if (vcpu && vcpu_to_hv_vcpu(vcpu)->vp_index == vpidx)
 		return vcpu;
 	kvm_for_each_vcpu(i, vcpu, kvm)
@@ -1044,7 +1046,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 
 	switch (msr) {
 	case HV_X64_MSR_VP_INDEX:
-		if (!host)
+		if (!host || (u32)data >= KVM_MAX_VCPUS)
 			return 1;
 		hv->vp_index = (u32)data;
 		break;
-- 
2.20.1

[PATCH AUTOSEL 4.19 012/167] KVM: x86: hyperv: consistently use 'hv_vcpu' for 'struct kvm_vcpu_hv' variables

[Sasha Levin]

From: Vitaly Kuznetsov <vkuznets@redhat.com>

[ Upstream commit 1779a39f786397760ae7a7cc03cf37697d8ae58d ]

Rename 'hv' to 'hv_vcpu' in kvm_hv_set_msr/kvm_hv_get_msr(); 'hv' is
'reserved' for 'struct kvm_hv' variables across the file.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/hyperv.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 73fa074b9089a..3f2775aac5545 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1042,20 +1042,20 @@ static u64 current_task_runtime_100ns(void)
 
 static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 {
-	struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;
+	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
 
 	switch (msr) {
 	case HV_X64_MSR_VP_INDEX:
 		if (!host || (u32)data >= KVM_MAX_VCPUS)
 			return 1;
-		hv->vp_index = (u32)data;
+		hv_vcpu->vp_index = (u32)data;
 		break;
 	case HV_X64_MSR_VP_ASSIST_PAGE: {
 		u64 gfn;
 		unsigned long addr;
 
 		if (!(data & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE)) {
-			hv->hv_vapic = data;
+			hv_vcpu->hv_vapic = data;
 			if (kvm_lapic_enable_pv_eoi(vcpu, 0))
 				return 1;
 			break;
@@ -1066,7 +1066,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 			return 1;
 		if (__clear_user((void __user *)addr, PAGE_SIZE))
 			return 1;
-		hv->hv_vapic = data;
+		hv_vcpu->hv_vapic = data;
 		kvm_vcpu_mark_page_dirty(vcpu, gfn);
 		if (kvm_lapic_enable_pv_eoi(vcpu,
 					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED))
@@ -1082,7 +1082,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 	case HV_X64_MSR_VP_RUNTIME:
 		if (!host)
 			return 1;
-		hv->runtime_offset = data - current_task_runtime_100ns();
+		hv_vcpu->runtime_offset = data - current_task_runtime_100ns();
 		break;
 	case HV_X64_MSR_SCONTROL:
 	case HV_X64_MSR_SVERSION:
@@ -1174,11 +1174,11 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
 			  bool host)
 {
 	u64 data = 0;
-	struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;
+	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
 
 	switch (msr) {
 	case HV_X64_MSR_VP_INDEX:
-		data = hv->vp_index;
+		data = hv_vcpu->vp_index;
 		break;
 	case HV_X64_MSR_EOI:
 		return kvm_hv_vapic_msr_read(vcpu, APIC_EOI, pdata);
@@ -1187,10 +1187,10 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
 	case HV_X64_MSR_TPR:
 		return kvm_hv_vapic_msr_read(vcpu, APIC_TASKPRI, pdata);
 	case HV_X64_MSR_VP_ASSIST_PAGE:
-		data = hv->hv_vapic;
+		data = hv_vcpu->hv_vapic;
 		break;
 	case HV_X64_MSR_VP_RUNTIME:
-		data = current_task_runtime_100ns() + hv->runtime_offset;
+		data = current_task_runtime_100ns() + hv_vcpu->runtime_offset;
 		break;
 	case HV_X64_MSR_SCONTROL:
 	case HV_X64_MSR_SVERSION:
-- 
2.20.1

[PATCH AUTOSEL 4.19 013/167] KVM: x86: hyperv: keep track of mismatched VP indexes

[Sasha Levin]

From: Vitaly Kuznetsov <vkuznets@redhat.com>

[ Upstream commit 87ee613d076351950b74383215437f841ebbeb75 ]

In most common cases VP index of a vcpu matches its vcpu index. Userspace
is, however, free to set any mapping it wishes and we need to account for
that when we need to find a vCPU with a particular VP index. To keep search
algorithms optimal in both cases introduce 'num_mismatched_vp_indexes'
counter showing how many vCPUs with mismatching VP index we have. In case
the counter is zero we can assume vp_index == vcpu_idx.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/include/asm/kvm_host.h |  3 +++
 arch/x86/kvm/hyperv.c           | 26 +++++++++++++++++++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3245b95ad2d97..b6417454a9d79 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -784,6 +784,9 @@ struct kvm_hv {
 	u64 hv_reenlightenment_control;
 	u64 hv_tsc_emulation_control;
 	u64 hv_tsc_emulation_status;
+
+	/* How many vCPUs have VP index != vCPU index */
+	atomic_t num_mismatched_vp_indexes;
 };
 
 enum kvm_irqchip_mode {
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 3f2775aac5545..2bb554b90b3c2 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1045,11 +1045,31 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 	struct kvm_vcpu_hv *hv_vcpu = &vcpu->arch.hyperv;
 
 	switch (msr) {
-	case HV_X64_MSR_VP_INDEX:
-		if (!host || (u32)data >= KVM_MAX_VCPUS)
+	case HV_X64_MSR_VP_INDEX: {
+		struct kvm_hv *hv = &vcpu->kvm->arch.hyperv;
+		int vcpu_idx = kvm_vcpu_get_idx(vcpu);
+		u32 new_vp_index = (u32)data;
+
+		if (!host || new_vp_index >= KVM_MAX_VCPUS)
 			return 1;
-		hv_vcpu->vp_index = (u32)data;
+
+		if (new_vp_index == hv_vcpu->vp_index)
+			return 0;
+
+		/*
+		 * The VP index is initialized to vcpu_index by
+		 * kvm_hv_vcpu_postcreate so they initially match.  Now the
+		 * VP index is changing, adjust num_mismatched_vp_indexes if
+		 * it now matches or no longer matches vcpu_idx.
+		 */
+		if (hv_vcpu->vp_index == vcpu_idx)
+			atomic_inc(&hv->num_mismatched_vp_indexes);
+		else if (new_vp_index == vcpu_idx)
+			atomic_dec(&hv->num_mismatched_vp_indexes);
+
+		hv_vcpu->vp_index = new_vp_index;
 		break;
+	}
 	case HV_X64_MSR_VP_ASSIST_PAGE: {
 		u64 gfn;
 		unsigned long addr;
-- 
2.20.1

[PATCH AUTOSEL 4.19 014/167] KVM: hyperv: define VP assist page helpers

[Sasha Levin]

From: Ladi Prosek <lprosek@redhat.com>

[ Upstream commit 72bbf9358c3676bd89dc4bd8fb0b1f2a11c288fc ]

The state related to the VP assist page is still managed by the LAPIC
code in the pv_eoi field.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/hyperv.c | 23 +++++++++++++++++++++--
 arch/x86/kvm/hyperv.h |  4 ++++
 arch/x86/kvm/lapic.c  |  4 ++--
 arch/x86/kvm/lapic.h  |  2 +-
 arch/x86/kvm/x86.c    |  2 +-
 5 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 2bb554b90b3c2..5842c5f587fe9 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -691,6 +691,24 @@ void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu)
 		stimer_cleanup(&hv_vcpu->stimer[i]);
 }
 
+bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu)
+{
+	if (!(vcpu->arch.hyperv.hv_vapic & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE))
+		return false;
+	return vcpu->arch.pv_eoi.msr_val & KVM_MSR_ENABLED;
+}
+EXPORT_SYMBOL_GPL(kvm_hv_assist_page_enabled);
+
+bool kvm_hv_get_assist_page(struct kvm_vcpu *vcpu,
+			    struct hv_vp_assist_page *assist_page)
+{
+	if (!kvm_hv_assist_page_enabled(vcpu))
+		return false;
+	return !kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.pv_eoi.data,
+				      assist_page, sizeof(*assist_page));
+}
+EXPORT_SYMBOL_GPL(kvm_hv_get_assist_page);
+
 static void stimer_prepare_msg(struct kvm_vcpu_hv_stimer *stimer)
 {
 	struct hv_message *msg = &stimer->msg;
@@ -1076,7 +1094,7 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 
 		if (!(data & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE)) {
 			hv_vcpu->hv_vapic = data;
-			if (kvm_lapic_enable_pv_eoi(vcpu, 0))
+			if (kvm_lapic_enable_pv_eoi(vcpu, 0, 0))
 				return 1;
 			break;
 		}
@@ -1089,7 +1107,8 @@ static int kvm_hv_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 		hv_vcpu->hv_vapic = data;
 		kvm_vcpu_mark_page_dirty(vcpu, gfn);
 		if (kvm_lapic_enable_pv_eoi(vcpu,
-					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED))
+					    gfn_to_gpa(gfn) | KVM_MSR_ENABLED,
+					    sizeof(struct hv_vp_assist_page)))
 			return 1;
 		break;
 	}
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index d6aa969e20f19..0e66c12ed2c3d 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -62,6 +62,10 @@ void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu);
 void kvm_hv_vcpu_postcreate(struct kvm_vcpu *vcpu);
 void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu);
 
+bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu);
+bool kvm_hv_get_assist_page(struct kvm_vcpu *vcpu,
+			    struct hv_vp_assist_page *assist_page);
+
 static inline struct kvm_vcpu_hv_stimer *vcpu_to_stimer(struct kvm_vcpu *vcpu,
 							int timer_index)
 {
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 031bd7f91f98a..ccf5a04de94c3 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2628,7 +2628,7 @@ int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
 	return 0;
 }
 
-int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data)
+int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned long len)
 {
 	u64 addr = data & ~KVM_MSR_ENABLED;
 	if (!IS_ALIGNED(addr, 4))
@@ -2638,7 +2638,7 @@ int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data)
 	if (!pv_eoi_enabled(vcpu))
 		return 0;
 	return kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.pv_eoi.data,
-					 addr, sizeof(u8));
+					 addr, len);
 }
 
 void kvm_apic_accept_events(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index ed0ed39abd369..ff6ef9c3d760c 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -120,7 +120,7 @@ static inline bool kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu)
 	return vcpu->arch.hyperv.hv_vapic & HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
 }
 
-int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data);
+int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned long len);
 void kvm_lapic_init(void);
 void kvm_lapic_exit(void);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e10a7a42449b3..ed6b43f344b0c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2494,7 +2494,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 
 		break;
 	case MSR_KVM_PV_EOI_EN:
-		if (kvm_lapic_enable_pv_eoi(vcpu, data))
+		if (kvm_lapic_enable_pv_eoi(vcpu, data, sizeof(u8)))
 			return 1;
 		break;
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 015/167] x86/kvm/lapic: preserve gfn_to_hva_cache len on cache reinit

[Sasha Levin]

From: Vitaly Kuznetsov <vkuznets@redhat.com>

[ Upstream commit a7c42bb6da6b1b54b2e7bd567636d72d87b10a79 ]

vcpu->arch.pv_eoi is accessible through both HV_X64_MSR_VP_ASSIST_PAGE and
MSR_KVM_PV_EOI_EN so on migration userspace may try to restore them in any
order. Values match, however, kvm_lapic_enable_pv_eoi() uses different
length: for Hyper-V case it's the whole struct hv_vp_assist_page, for KVM
native case it is 8. In case we restore KVM-native MSR last cache will
be reinitialized with len=8 so trying to access VP assist page beyond
8 bytes with kvm_read_guest_cached() will fail.

Check if we re-initializing cache for the same address and preserve length
in case it was greater.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/lapic.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ccf5a04de94c3..973a244081d34 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2631,14 +2631,22 @@ int kvm_hv_vapic_msr_read(struct kvm_vcpu *vcpu, u32 reg, u64 *data)
 int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data, unsigned long len)
 {
 	u64 addr = data & ~KVM_MSR_ENABLED;
+	struct gfn_to_hva_cache *ghc = &vcpu->arch.pv_eoi.data;
+	unsigned long new_len;
+
 	if (!IS_ALIGNED(addr, 4))
 		return 1;
 
 	vcpu->arch.pv_eoi.msr_val = data;
 	if (!pv_eoi_enabled(vcpu))
 		return 0;
-	return kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.pv_eoi.data,
-					 addr, len);
+
+	if (addr == ghc->gpa && len <= ghc->len)
+		new_len = ghc->len;
+	else
+		new_len = len;
+
+	return kvm_gfn_to_hva_cache_init(vcpu->kvm, ghc, addr, new_len);
 }
 
 void kvm_apic_accept_events(struct kvm_vcpu *vcpu)
-- 
2.20.1

[PATCH AUTOSEL 4.19 065/167] KVM: VMX: Compare only a single byte for VMCS' "launched" in vCPU-run

[Sasha Levin]

From: Sean Christopherson <sean.j.christopherson@intel.com>

[ Upstream commit 61c08aa9606d4e48a8a50639c956448a720174c3 ]

The vCPU-run asm blob does a manual comparison of a VMCS' launched
status to execute the correct VM-Enter instruction, i.e. VMLAUNCH vs.
VMRESUME.  The launched flag is a bool, which is a typedef of _Bool.
C99 does not define an exact size for _Bool, stating only that is must
be large enough to hold '0' and '1'.  Most, if not all, compilers use
a single byte for _Bool, including gcc[1].

Originally, 'launched' was of type 'int' and so the asm blob used 'cmpl'
to check the launch status.  When 'launched' was moved to be stored on a
per-VMCS basis, struct vcpu_vmx's "temporary" __launched flag was added
in order to avoid having to pass the current VMCS into the asm blob.
The new  '__launched' was defined as a 'bool' and not an 'int', but the
'cmp' instruction was not updated.

This has not caused any known problems, likely due to compilers aligning
variables to 4-byte or 8-byte boundaries and KVM zeroing out struct
vcpu_vmx during allocation.  I.e. vCPU-run accesses "junk" data, it just
happens to always be zero and so doesn't affect the result.

[1] https://gcc.gnu.org/ml/gcc-patches/2000-10/msg01127.html

Fixes: d462b8192368 ("KVM: VMX: Keep list of loaded VMCSs, instead of vcpus")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/vmx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2e310ea62d609..562f5dc4645b6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10808,7 +10808,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 		"mov %%" _ASM_AX", %%cr2 \n\t"
 		"3: \n\t"
 		/* Check if vmlaunch of vmresume is needed */
-		"cmpl $0, %c[launched](%0) \n\t"
+		"cmpb $0, %c[launched](%0) \n\t"
 		/* Load guest registers.  Don't clobber flags. */
 		"mov %c[rax](%0), %%" _ASM_AX " \n\t"
 		"mov %c[rbx](%0), %%" _ASM_BX " \n\t"
-- 
2.20.1

[PATCH AUTOSEL 4.19 073/167] x86/kvmclock: set offset for kvm unstable clock

[Sasha Levin]

From: Pavel Tatashin <pasha.tatashin@soleen.com>

[ Upstream commit b5179ec4187251a751832193693d6e474d3445ac ]

VMs may show incorrect uptime and dmesg printk offsets on hypervisors with
unstable clock. The problem is produced when VM is rebooted without exiting
from qemu.

The fix is to calculate clock offset not only for stable clock but for
unstable clock as well, and use kvm_sched_clock_read() which substracts
the offset for both clocks.

This is safe, because pvclock_clocksource_read() does the right thing and
makes sure that clock always goes forward, so once offset is calculated
with unstable clock, we won't get new reads that are smaller than offset,
and thus won't get negative results.

Thank you Jon DeVree for helping to reproduce this issue.

Fixes: 857baa87b642 ("sched/clock: Enable sched clock early")
Cc: stable@vger.kernel.org
Reported-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/kvmclock.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 013fe3d21dbb3..2ec202cb9dfd4 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -117,12 +117,8 @@ static u64 kvm_sched_clock_read(void)
 
 static inline void kvm_sched_clock_init(bool stable)
 {
-	if (!stable) {
-		pv_time_ops.sched_clock = kvm_clock_read;
+	if (!stable)
 		clear_sched_clock_stable();
-		return;
-	}
-
 	kvm_sched_clock_offset = kvm_clock_read();
 	pv_time_ops.sched_clock = kvm_sched_clock_read;
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 092/167] kvm: mmu: Fix overflow on kvm mmu page limit calculation

[Sasha Levin]

From: Ben Gardon <bgardon@google.com>

[ Upstream commit bc8a3d8925a8fa09fa550e0da115d95851ce33c6 ]

KVM bases its memory usage limits on the total number of guest pages
across all memslots. However, those limits, and the calculations to
produce them, use 32 bit unsigned integers. This can result in overflow
if a VM has more guest pages that can be represented by a u32. As a
result of this overflow, KVM can use a low limit on the number of MMU
pages it will allocate. This makes KVM unable to map all of guest memory
at once, prompting spurious faults.

Tested: Ran all kvm-unit-tests on an Intel Haswell machine. This patch
	introduced no new failures.

Signed-off-by: Ben Gardon <bgardon@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/include/asm/kvm_host.h | 12 ++++++------
 arch/x86/kvm/mmu.c              | 13 ++++++-------
 arch/x86/kvm/mmu.h              |  2 +-
 arch/x86/kvm/x86.c              |  4 ++--
 4 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b6417454a9d79..0d3f5cf3ff3ea 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -117,7 +117,7 @@ static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level)
 }
 
 #define KVM_PERMILLE_MMU_PAGES 20
-#define KVM_MIN_ALLOC_MMU_PAGES 64
+#define KVM_MIN_ALLOC_MMU_PAGES 64UL
 #define KVM_MMU_HASH_SHIFT 12
 #define KVM_NUM_MMU_PAGES (1 << KVM_MMU_HASH_SHIFT)
 #define KVM_MIN_FREE_MMU_PAGES 5
@@ -796,9 +796,9 @@ enum kvm_irqchip_mode {
 };
 
 struct kvm_arch {
-	unsigned int n_used_mmu_pages;
-	unsigned int n_requested_mmu_pages;
-	unsigned int n_max_mmu_pages;
+	unsigned long n_used_mmu_pages;
+	unsigned long n_requested_mmu_pages;
+	unsigned long n_max_mmu_pages;
 	unsigned int indirect_shadow_pages;
 	unsigned long mmu_valid_gen;
 	struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES];
@@ -1201,8 +1201,8 @@ void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
 				   gfn_t gfn_offset, unsigned long mask);
 void kvm_mmu_zap_all(struct kvm *kvm);
 void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen);
-unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm);
-void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
+unsigned long kvm_mmu_calculate_mmu_pages(struct kvm *kvm);
+void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long kvm_nr_mmu_pages);
 
 int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3);
 bool pdptrs_changed(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index cdc0c460950f3..88940261fb537 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1954,7 +1954,7 @@ static int is_empty_shadow_page(u64 *spt)
  * aggregate version in order to make the slab shrinker
  * faster
  */
-static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr)
+static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, unsigned long nr)
 {
 	kvm->arch.n_used_mmu_pages += nr;
 	percpu_counter_add(&kvm_total_used_mmu_pages, nr);
@@ -2704,7 +2704,7 @@ static bool prepare_zap_oldest_mmu_page(struct kvm *kvm,
  * Changing the number of mmu pages allocated to the vm
  * Note: if goal_nr_mmu_pages is too small, you will get dead lock
  */
-void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages)
+void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long goal_nr_mmu_pages)
 {
 	LIST_HEAD(invalid_list);
 
@@ -5926,10 +5926,10 @@ int kvm_mmu_module_init(void)
 /*
  * Caculate mmu pages needed for kvm.
  */
-unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
+unsigned long kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
 {
-	unsigned int nr_mmu_pages;
-	unsigned int  nr_pages = 0;
+	unsigned long nr_mmu_pages;
+	unsigned long nr_pages = 0;
 	struct kvm_memslots *slots;
 	struct kvm_memory_slot *memslot;
 	int i;
@@ -5942,8 +5942,7 @@ unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
 	}
 
 	nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
-	nr_mmu_pages = max(nr_mmu_pages,
-			   (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
+	nr_mmu_pages = max(nr_mmu_pages, KVM_MIN_ALLOC_MMU_PAGES);
 
 	return nr_mmu_pages;
 }
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 1fab69c0b2f32..65892288bf510 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -69,7 +69,7 @@ bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu);
 int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
 				u64 fault_address, char *insn, int insn_len);
 
-static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm)
+static inline unsigned long kvm_mmu_available_pages(struct kvm *kvm)
 {
 	if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages)
 		return kvm->arch.n_max_mmu_pages -
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ed6b43f344b0c..4f564dc17c333 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4116,7 +4116,7 @@ static int kvm_vm_ioctl_set_identity_map_addr(struct kvm *kvm,
 }
 
 static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
-					  u32 kvm_nr_mmu_pages)
+					 unsigned long kvm_nr_mmu_pages)
 {
 	if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES)
 		return -EINVAL;
@@ -4130,7 +4130,7 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
 	return 0;
 }
 
-static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
+static unsigned long kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm)
 {
 	return kvm->arch.n_max_mmu_pages;
 }
-- 
2.20.1

[PATCH AUTOSEL 4.19 093/167] x86/kvm: move kvm_load/put_guest_xcr0 into atomic context

[Sasha Levin]

From: WANG Chao <chao.wang@ucloud.cn>

[ Upstream commit 1811d979c71621aafc7b879477202d286f7e863b ]

guest xcr0 could leak into host when MCE happens in guest mode. Because
do_machine_check() could schedule out at a few places.

For example:

kvm_load_guest_xcr0
...
kvm_x86_ops->run(vcpu) {
  vmx_vcpu_run
    vmx_complete_atomic_exit
      kvm_machine_check
        do_machine_check
          do_memory_failure
            memory_failure
              lock_page

In this case, host_xcr0 is 0x2ff, guest vcpu xcr0 is 0xff. After schedule
out, host cpu has guest xcr0 loaded (0xff).

In __switch_to {
     switch_fpu_finish
       copy_kernel_to_fpregs
         XRSTORS

If any bit i in XSTATE_BV[i] == 1 and xcr0[i] == 0, XRSTORS will
generate #GP (In this case, bit 9). Then ex_handler_fprestore kicks in
and tries to reinitialize fpu by restoring init fpu state. Same story as
last #GP, except we get DOUBLE FAULT this time.

Cc: stable@vger.kernel.org
Signed-off-by: WANG Chao <chao.wang@ucloud.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm.c |  2 ++
 arch/x86/kvm/vmx.c |  4 ++++
 arch/x86/kvm/x86.c | 10 ++++------
 arch/x86/kvm/x86.h |  2 ++
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 0f33f00aa4dfe..ac2cc2ed7a85f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5622,6 +5622,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	svm->vmcb->save.cr2 = vcpu->arch.cr2;
 
 	clgi();
+	kvm_load_guest_xcr0(vcpu);
 
 	/*
 	 * If this vCPU has touched SPEC_CTRL, restore the guest's value if
@@ -5769,6 +5770,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
 	if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
 		kvm_before_interrupt(&svm->vcpu);
 
+	kvm_put_guest_xcr0(vcpu);
 	stgi();
 
 	/* Any pending NMI will happen here */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 562f5dc4645b6..ee9ff20da3902 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10756,6 +10756,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)
 		vmx_set_interrupt_shadow(vcpu, 0);
 
+	kvm_load_guest_xcr0(vcpu);
+
 	if (static_cpu_has(X86_FEATURE_PKU) &&
 	    kvm_read_cr4_bits(vcpu, X86_CR4_PKE) &&
 	    vcpu->arch.pkru != vmx->host_pkru)
@@ -10971,6 +10973,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 			__write_pkru(vmx->host_pkru);
 	}
 
+	kvm_put_guest_xcr0(vcpu);
+
 	vmx->nested.nested_run_pending = 0;
 	vmx->idt_vectoring_info = 0;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4f564dc17c333..253326aaea9ac 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -713,7 +713,7 @@ void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
 }
 EXPORT_SYMBOL_GPL(kvm_lmsw);
 
-static void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu)
+void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu)
 {
 	if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&
 			!vcpu->guest_xcr0_loaded) {
@@ -723,8 +723,9 @@ static void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu)
 		vcpu->guest_xcr0_loaded = 1;
 	}
 }
+EXPORT_SYMBOL_GPL(kvm_load_guest_xcr0);
 
-static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
+void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
 {
 	if (vcpu->guest_xcr0_loaded) {
 		if (vcpu->arch.xcr0 != host_xcr0)
@@ -732,6 +733,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
 		vcpu->guest_xcr0_loaded = 0;
 	}
 }
+EXPORT_SYMBOL_GPL(kvm_put_guest_xcr0);
 
 static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
 {
@@ -7648,8 +7650,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		goto cancel_injection;
 	}
 
-	kvm_load_guest_xcr0(vcpu);
-
 	if (req_immediate_exit) {
 		kvm_make_request(KVM_REQ_EVENT, vcpu);
 		kvm_x86_ops->request_immediate_exit(vcpu);
@@ -7702,8 +7702,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	vcpu->mode = OUTSIDE_GUEST_MODE;
 	smp_wmb();
 
-	kvm_put_guest_xcr0(vcpu);
-
 	kvm_before_interrupt(vcpu);
 	kvm_x86_ops->handle_external_intr(vcpu);
 	kvm_after_interrupt(vcpu);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 1826ed9dd1c8f..8889e0c029a70 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -345,4 +345,6 @@ static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu)
 	__this_cpu_write(current_vcpu, NULL);
 }
 
+void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu);
+void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu);
 #endif
-- 
2.20.1

[PATCH AUTOSEL 4.19 094/167] KVM: x86: Always use 32-bit SMRAM save state for 32-bit kernels

[Sasha Levin]

From: Sean Christopherson <sean.j.christopherson@intel.com>

[ Upstream commit b68f3cc7d978943fcf85148165b00594c38db776 ]

Invoking the 64-bit variation on a 32-bit kenrel will crash the guest,
trigger a WARN, and/or lead to a buffer overrun in the host, e.g.
rsm_load_state_64() writes r8-r15 unconditionally, but enum kvm_reg and
thus x86_emulate_ctxt._regs only define r8-r15 for CONFIG_X86_64.

KVM allows userspace to report long mode support via CPUID, even though
the guest is all but guaranteed to crash if it actually tries to enable
long mode.  But, a pure 32-bit guest that is ignorant of long mode will
happily plod along.

SMM complicates things as 64-bit CPUs use a different SMRAM save state
area.  KVM handles this correctly for 64-bit kernels, e.g. uses the
legacy save state map if userspace has hid long mode from the guest,
but doesn't fare well when userspace reports long mode support on a
32-bit host kernel (32-bit KVM doesn't support 64-bit guests).

Since the alternative is to crash the guest, e.g. by not loading state
or explicitly requesting shutdown, unconditionally use the legacy SMRAM
save state map for 32-bit KVM.  If a guest has managed to get far enough
to handle SMIs when running under a weird/buggy userspace hypervisor,
then don't deliberately crash the guest since there are no downsides
(from KVM's perspective) to allow it to continue running.

Fixes: 660a5d517aaab ("KVM: x86: save/load state on SMM switch")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/emulate.c | 10 ++++++++++
 arch/x86/kvm/x86.c     | 10 ++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 4a688ef9e4481..429728b35bca1 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2331,12 +2331,16 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt)
 
 static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt)
 {
+#ifdef CONFIG_X86_64
 	u32 eax, ebx, ecx, edx;
 
 	eax = 0x80000001;
 	ecx = 0;
 	ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false);
 	return edx & bit(X86_FEATURE_LM);
+#else
+	return false;
+#endif
 }
 
 #define GET_SMSTATE(type, smbase, offset)				  \
@@ -2381,6 +2385,7 @@ static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
 	return X86EMUL_CONTINUE;
 }
 
+#ifdef CONFIG_X86_64
 static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
 {
 	struct desc_struct desc;
@@ -2399,6 +2404,7 @@ static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
 	ctxt->ops->set_segment(ctxt, selector, &desc, base3, n);
 	return X86EMUL_CONTINUE;
 }
+#endif
 
 static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
 				    u64 cr0, u64 cr3, u64 cr4)
@@ -2499,6 +2505,7 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase)
 	return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4);
 }
 
+#ifdef CONFIG_X86_64
 static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
 {
 	struct desc_struct desc;
@@ -2560,6 +2567,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
 
 	return X86EMUL_CONTINUE;
 }
+#endif
 
 static int em_rsm(struct x86_emulate_ctxt *ctxt)
 {
@@ -2616,9 +2624,11 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 	if (ctxt->ops->pre_leave_smm(ctxt, smbase))
 		return X86EMUL_UNHANDLEABLE;
 
+#ifdef CONFIG_X86_64
 	if (emulator_has_longmode(ctxt))
 		ret = rsm_load_state_64(ctxt, smbase + 0x8000);
 	else
+#endif
 		ret = rsm_load_state_32(ctxt, smbase + 0x8000);
 
 	if (ret != X86EMUL_CONTINUE) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 253326aaea9ac..1b80b4bd0fbf2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7226,9 +7226,9 @@ static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, char *buf)
 	put_smstate(u32, buf, 0x7ef8, vcpu->arch.smbase);
 }
 
+#ifdef CONFIG_X86_64
 static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf)
 {
-#ifdef CONFIG_X86_64
 	struct desc_ptr dt;
 	struct kvm_segment seg;
 	unsigned long val;
@@ -7278,10 +7278,8 @@ static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf)
 
 	for (i = 0; i < 6; i++)
 		enter_smm_save_seg_64(vcpu, buf, i);
-#else
-	WARN_ON_ONCE(1);
-#endif
 }
+#endif
 
 static void enter_smm(struct kvm_vcpu *vcpu)
 {
@@ -7292,9 +7290,11 @@ static void enter_smm(struct kvm_vcpu *vcpu)
 
 	trace_kvm_enter_smm(vcpu->vcpu_id, vcpu->arch.smbase, true);
 	memset(buf, 0, 512);
+#ifdef CONFIG_X86_64
 	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
 		enter_smm_save_state_64(vcpu, buf);
 	else
+#endif
 		enter_smm_save_state_32(vcpu, buf);
 
 	/*
@@ -7352,8 +7352,10 @@ static void enter_smm(struct kvm_vcpu *vcpu)
 	kvm_set_segment(vcpu, &ds, VCPU_SREG_GS);
 	kvm_set_segment(vcpu, &ds, VCPU_SREG_SS);
 
+#ifdef CONFIG_X86_64
 	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
 		kvm_x86_ops->set_efer(vcpu, 0);
+#endif
 
 	kvm_update_cpuid(vcpu);
 	kvm_mmu_reset_context(vcpu);
-- 
2.20.1

[PATCH AUTOSEL 4.19 115/167] kvm: Check irqchip mode before assign irqfd

[Sasha Levin]

From: Peter Xu <peterx@redhat.com>

[ Upstream commit 654f1f13ea56b92bacade8ce2725aea0457f91c0 ]

When assigning kvm irqfd we didn't check the irqchip mode but we allow
KVM_IRQFD to succeed with all the irqchip modes.  However it does not
make much sense to create irqfd even without the kernel chips.  Let's
provide a arch-dependent helper to check whether a specific irqfd is
allowed by the arch.  At least for x86, it should make sense to check:

- when irqchip mode is NONE, all irqfds should be disallowed, and,

- when irqchip mode is SPLIT, irqfds that are with resamplefd should
  be disallowed.

For either of the case, previously we'll silently ignore the irq or
the irq ack event if the irqchip mode is incorrect.  However that can
cause misterious guest behaviors and it can be hard to triage.  Let's
fail KVM_IRQFD even earlier to detect these incorrect configurations.

CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Radim Krčmář <rkrcmar@redhat.com>
CC: Alex Williamson <alex.williamson@redhat.com>
CC: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/irq.c | 7 +++++++
 arch/x86/kvm/irq.h | 1 +
 virt/kvm/eventfd.c | 9 +++++++++
 3 files changed, 17 insertions(+)

diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index faa264822cee3..007bc654f928a 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -172,3 +172,10 @@ void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 	__kvm_migrate_apic_timer(vcpu);
 	__kvm_migrate_pit_timer(vcpu);
 }
+
+bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
+{
+	bool resample = args->flags & KVM_IRQFD_FLAG_RESAMPLE;
+
+	return resample ? irqchip_kernel(kvm) : irqchip_in_kernel(kvm);
+}
diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
index d5005cc265217..fd210cdd49839 100644
--- a/arch/x86/kvm/irq.h
+++ b/arch/x86/kvm/irq.h
@@ -114,6 +114,7 @@ static inline int irqchip_in_kernel(struct kvm *kvm)
 	return mode != KVM_IRQCHIP_NONE;
 }
 
+bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args);
 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu);
 void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu);
 void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu);
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index b20b751286fc6..757a17f5ebdeb 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -44,6 +44,12 @@
 
 static struct workqueue_struct *irqfd_cleanup_wq;
 
+bool __attribute__((weak))
+kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
+{
+	return true;
+}
+
 static void
 irqfd_inject(struct work_struct *work)
 {
@@ -297,6 +303,9 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	if (!kvm_arch_intc_initialized(kvm))
 		return -EAGAIN;
 
+	if (!kvm_arch_irqfd_allowed(kvm, args))
+		return -EINVAL;
+
 	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
 	if (!irqfd)
 		return -ENOMEM;
-- 
2.20.1

[PATCH AUTOSEL 4.19 132/167] KVM: x86: optimize check for valid PAT value

[Sasha Levin]

From: Paolo Bonzini <pbonzini@redhat.com>

[ Upstream commit 674ea351cdeb01d2740edce31db7f2d79ce6095d ]

This check will soon be done on every nested vmentry and vmexit,
"parallelize" it using bitwise operations.

Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/mtrr.c | 10 +---------
 arch/x86/kvm/vmx.c  |  2 +-
 arch/x86/kvm/x86.h  | 10 ++++++++++
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
index e9ea2d45ae66b..9f72cc427158e 100644
--- a/arch/x86/kvm/mtrr.c
+++ b/arch/x86/kvm/mtrr.c
@@ -48,11 +48,6 @@ static bool msr_mtrr_valid(unsigned msr)
 	return false;
 }
 
-static bool valid_pat_type(unsigned t)
-{
-	return t < 8 && (1 << t) & 0xf3; /* 0, 1, 4, 5, 6, 7 */
-}
-
 static bool valid_mtrr_type(unsigned t)
 {
 	return t < 8 && (1 << t) & 0x73; /* 0, 1, 4, 5, 6 */
@@ -67,10 +62,7 @@ bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data)
 		return false;
 
 	if (msr == MSR_IA32_CR_PAT) {
-		for (i = 0; i < 8; i++)
-			if (!valid_pat_type((data >> (i * 8)) & 0xff))
-				return false;
-		return true;
+		return kvm_pat_valid(data);
 	} else if (msr == MSR_MTRRdefType) {
 		if (data & ~0xcff)
 			return false;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ee9ff20da3902..feff7ed44a2bb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4266,7 +4266,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		break;
 	case MSR_IA32_CR_PAT:
 		if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
-			if (!kvm_mtrr_valid(vcpu, MSR_IA32_CR_PAT, data))
+			if (!kvm_pat_valid(data))
 				return 1;
 			vmcs_write64(GUEST_IA32_PAT, data);
 			vcpu->arch.pat = data;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 8889e0c029a70..3a91ea760f073 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -345,6 +345,16 @@ static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu)
 	__this_cpu_write(current_vcpu, NULL);
 }
 
+
+static inline bool kvm_pat_valid(u64 data)
+{
+	if (data & 0xF8F8F8F8F8F8F8F8ull)
+		return false;
+	/* 0, 1, 4, 5, 6, 7 are valid values.  */
+	return (data | ((data & 0x0202020202020202ull) << 1)) == data;
+}
+
 void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu);
 void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu);
+
 #endif
-- 
2.20.1

[PATCH AUTOSEL 4.19 133/167] KVM: VMX: Always signal #GP on WRMSR to MSR_IA32_CR_PAT with bad value

[Sasha Levin]

From: Sean Christopherson <sean.j.christopherson@intel.com>

[ Upstream commit d28f4290b53a157191ed9991ad05dffe9e8c0c89 ]

The behavior of WRMSR is in no way dependent on whether or not KVM
consumes the value.

Fixes: 4566654bb9be9 ("KVM: vmx: Inject #GP on invalid PAT CR")
Cc: stable@vger.kernel.org
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/vmx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index feff7ed44a2bb..e4bba840a0708 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4265,9 +4265,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 					      MSR_TYPE_W);
 		break;
 	case MSR_IA32_CR_PAT:
+		if (!kvm_pat_valid(data))
+			return 1;
+
 		if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) {
-			if (!kvm_pat_valid(data))
-				return 1;
 			vmcs_write64(GUEST_IA32_PAT, data);
 			vcpu->arch.pat = data;
 			break;
-- 
2.20.1

[PATCH AUTOSEL 4.19 134/167] KVM: VMX: Fix handling of #MC that occurs during VM-Entry

[Sasha Levin]

From: Sean Christopherson <sean.j.christopherson@intel.com>

[ Upstream commit beb8d93b3e423043e079ef3dda19dad7b28467a8 ]

A previous fix to prevent KVM from consuming stale VMCS state after a
failed VM-Entry inadvertantly blocked KVM's handling of machine checks
that occur during VM-Entry.

Per Intel's SDM, a #MC during VM-Entry is handled in one of three ways,
depending on when the #MC is recognoized.  As it pertains to this bug
fix, the third case explicitly states EXIT_REASON_MCE_DURING_VMENTRY
is handled like any other VM-Exit during VM-Entry, i.e. sets bit 31 to
indicate the VM-Entry failed.

If a machine-check event occurs during a VM entry, one of the following occurs:
 - The machine-check event is handled as if it occurred before the VM entry:
        ...
 - The machine-check event is handled after VM entry completes:
        ...
 - A VM-entry failure occurs as described in Section 26.7. The basic
   exit reason is 41, for "VM-entry failure due to machine-check event".

Explicitly handle EXIT_REASON_MCE_DURING_VMENTRY as a one-off case in
vmx_vcpu_run() instead of binning it into vmx_complete_atomic_exit().
Doing so allows vmx_vcpu_run() to handle VMX_EXIT_REASONS_FAILED_VMENTRY
in a sane fashion and also simplifies vmx_complete_atomic_exit() since
VMCS.VM_EXIT_INTR_INFO is guaranteed to be fresh.

Fixes: b060ca3b2e9e7 ("kvm: vmx: Handle VMLAUNCH/VMRESUME failure properly")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/vmx.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e4bba840a0708..82253d31842a2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10438,28 +10438,21 @@ static void vmx_apicv_post_state_restore(struct kvm_vcpu *vcpu)
 
 static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
 {
-	u32 exit_intr_info = 0;
-	u16 basic_exit_reason = (u16)vmx->exit_reason;
-
-	if (!(basic_exit_reason == EXIT_REASON_MCE_DURING_VMENTRY
-	      || basic_exit_reason == EXIT_REASON_EXCEPTION_NMI))
+	if (vmx->exit_reason != EXIT_REASON_EXCEPTION_NMI)
 		return;
 
-	if (!(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
-		exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
-	vmx->exit_intr_info = exit_intr_info;
+	vmx->exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
 
 	/* if exit due to PF check for async PF */
-	if (is_page_fault(exit_intr_info))
+	if (is_page_fault(vmx->exit_intr_info))
 		vmx->vcpu.arch.apf.host_apf_reason = kvm_read_and_reset_pf_reason();
 
 	/* Handle machine checks before interrupts are enabled */
-	if (basic_exit_reason == EXIT_REASON_MCE_DURING_VMENTRY ||
-	    is_machine_check(exit_intr_info))
+	if (is_machine_check(vmx->exit_intr_info))
 		kvm_machine_check();
 
 	/* We need to handle NMIs before interrupts are enabled */
-	if (is_nmi(exit_intr_info)) {
+	if (is_nmi(vmx->exit_intr_info)) {
 		kvm_before_interrupt(&vmx->vcpu);
 		asm("int $2");
 		kvm_after_interrupt(&vmx->vcpu);
@@ -10980,6 +10973,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
 	vmx->idt_vectoring_info = 0;
 
 	vmx->exit_reason = vmx->fail ? 0xdead : vmcs_read32(VM_EXIT_REASON);
+	if ((u16)vmx->exit_reason == EXIT_REASON_MCE_DURING_VMENTRY)
+		kvm_machine_check();
+
 	if (vmx->fail || (vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY))
 		return;
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 135/167] KVM: VMX: check CPUID before allowing read/write of IA32_XSS

[Sasha Levin]

From: Wanpeng Li <wanpengli@tencent.com>

[ Upstream commit 4d763b168e9c5c366b05812c7bba7662e5ea3669 ]

Raise #GP when guest read/write IA32_XSS, but the CPUID bits
say that it shouldn't exist.

Fixes: 203000993de5 (kvm: vmx: add MSR logic for XSAVES)
Reported-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Reported-by: Tao Xu <tao3.xu@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/vmx.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 82253d31842a2..2938b4bcc9684 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4135,7 +4135,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		return vmx_get_vmx_msr(&vmx->nested.msrs, msr_info->index,
 				       &msr_info->data);
 	case MSR_IA32_XSS:
-		if (!vmx_xsaves_supported())
+		if (!vmx_xsaves_supported() ||
+		    (!msr_info->host_initiated &&
+		     !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
+		       guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
 			return 1;
 		msr_info->data = vcpu->arch.ia32_xss;
 		break;
@@ -4302,7 +4305,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			return 1;
 		return vmx_set_vmx_msr(vcpu, msr_index, data);
 	case MSR_IA32_XSS:
-		if (!vmx_xsaves_supported())
+		if (!vmx_xsaves_supported() ||
+		    (!msr_info->host_initiated &&
+		     !(guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) &&
+		       guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))))
 			return 1;
 		/*
 		 * The only supported bit as of Skylake is bit 8, but
-- 
2.20.1

[PATCH AUTOSEL 4.19 162/167] virtio/s390: fix race on airq_areas[]

[Sasha Levin]

From: Halil Pasic <pasic@linux.ibm.com>

[ Upstream commit 4f419eb14272e0698e8c55bb5f3f266cc2a21c81 ]

The access to airq_areas was racy ever since the adapter interrupts got
introduced to virtio-ccw, but since commit 39c7dcb15892 ("virtio/s390:
make airq summary indicators DMA") this became an issue in practice as
well. Namely before that commit the airq_info that got overwritten was
still functional. After that commit however the two infos share a
summary_indicator, which aggravates the situation. Which means
auto-online mechanism occasionally hangs the boot with virtio_blk.

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 96b14536d935 ("virtio-ccw: virtio-ccw adapter interrupt support.")
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/virtio/virtio_ccw.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index ec54538f7ae1c..67efdf25657f3 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -132,6 +132,7 @@ struct airq_info {
 	struct airq_iv *aiv;
 };
 static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
+static DEFINE_MUTEX(airq_areas_lock);
 
 #define CCW_CMD_SET_VQ 0x13
 #define CCW_CMD_VDEV_RESET 0x33
@@ -244,9 +245,11 @@ static unsigned long get_airq_indicator(struct virtqueue *vqs[], int nvqs,
 	unsigned long bit, flags;
 
 	for (i = 0; i < MAX_AIRQ_AREAS && !indicator_addr; i++) {
+		mutex_lock(&airq_areas_lock);
 		if (!airq_areas[i])
 			airq_areas[i] = new_airq_info();
 		info = airq_areas[i];
+		mutex_unlock(&airq_areas_lock);
 		if (!info)
 			return 0;
 		write_lock_irqsave(&info->lock, flags);
-- 
2.20.1