[PULL v2 0/6] KVM/ARM Fixes for v4.12-rc5 - Take 2

[PULL v2 0/6] KVM/ARM Fixes for v4.12-rc5 - Take 2

[Christoffer Dall]

Hi Radim and Paolo,

Six additional fixes for KVM/ARM for v4.12 (instead of only the first
three in the first version of this pull request).

The changes are:
 - Fix an issue with migrating GICv2 VMs on GICv3 systems.
 - Squashed a bug for gicv3 when figuring out preemption levels.
 - Fix a potential null pointer derefence in KVM happening under memory
   pressure.
 - Maintain RES1 bits in the SCTLR_EL2 to make sure KVM works on new
   architecture revisions.
 - Allow unaligned accesses at EL2/HYP

The following changes since commit fa472fa91a5a0b241f5ddae927d2e235d07545df:

  KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices (2017-05-18 11:18:16 +0200)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git kvm-arm-for-v4.12-rc5-take2

for you to fetch changes up to 33b5c38852b29736f3b472dd095c9a18ec22746f:

  arm: KVM: Allow unaligned accesses at HYP (2017-06-06 22:20:02 +0200)

Thanks,
-Christoffer

---
Christoffer Dall (2):
      KVM: arm/arm64: Fix isues with GICv2 on GICv3 migration
      KVM: arm/arm64: vgic-v3: Fix nr_pre_bits bitfield extraction

Marc Zyngier (4):
      KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages
      arm64: KVM: Preserve RES1 bits in SCTLR_EL2
      arm64: KVM: Allow unaligned accesses at EL2
      arm: KVM: Allow unaligned accesses at HYP

 arch/arm/kvm/init.S                |  5 ++--
 arch/arm64/include/asm/sysreg.h    |  4 ++++
 arch/arm64/kvm/hyp-init.S          | 11 +++++----
 arch/arm64/kvm/vgic-sys-reg-v3.c   | 10 ++++----
 include/linux/irqchip/arm-gic-v3.h |  4 ++++
 include/linux/irqchip/arm-gic.h    | 28 ++++++++++++++++++++---
 virt/kvm/arm/hyp/vgic-v3-sr.c      |  2 +-
 virt/kvm/arm/mmu.c                 |  3 +++
 virt/kvm/arm/vgic/vgic-mmio-v2.c   | 16 +++++++++++--
 virt/kvm/arm/vgic/vgic-v2.c        | 28 ++++++++++++++++++++---
 virt/kvm/arm/vgic/vgic-v3.c        | 47 ++++++++++++++++++++++++++------------
 virt/kvm/arm/vgic/vgic.h           | 12 ++++++----
 12 files changed, 131 insertions(+), 39 deletions(-)

[PULL v2 1/6] KVM: arm/arm64: Fix isues with GICv2 on GICv3 migration

[Christoffer Dall]

We have been a little loose with our intermediate VMCR representation
where we had a 'ctlr' field, but we failed to differentiate between the
GICv2 GICC_CTLR and ICC_CTLR_EL1 layouts, and therefore ended up mapping
the wrong bits into the individual fields of the ICH_VMCR_EL2 when
emulating a GICv2 on a GICv3 system.

Fix this by using explicit fields for the VMCR bits instead.

Cc: Eric Auger <eric.auger@redhat.com>
Reported-by: wanghaibin <wanghaibin.wang@huawei.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/vgic-sys-reg-v3.c   | 10 ++++----
 include/linux/irqchip/arm-gic-v3.h |  4 ++++
 include/linux/irqchip/arm-gic.h    | 28 ++++++++++++++++++++---
 virt/kvm/arm/vgic/vgic-mmio-v2.c   | 16 +++++++++++--
 virt/kvm/arm/vgic/vgic-v2.c        | 28 ++++++++++++++++++++---
 virt/kvm/arm/vgic/vgic-v3.c        | 47 ++++++++++++++++++++++++++------------
 virt/kvm/arm/vgic/vgic.h           | 12 ++++++----
 7 files changed, 114 insertions(+), 31 deletions(-)

diff --git a/arch/arm64/kvm/vgic-sys-reg-v3.c b/arch/arm64/kvm/vgic-sys-reg-v3.c
index 79f37e3..6260b69 100644
--- a/arch/arm64/kvm/vgic-sys-reg-v3.c
+++ b/arch/arm64/kvm/vgic-sys-reg-v3.c
@@ -65,8 +65,8 @@ static bool access_gic_ctlr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		 * Here set VMCR.CTLR in ICC_CTLR_EL1 layout.
 		 * The vgic_set_vmcr() will convert to ICH_VMCR layout.
 		 */
-		vmcr.ctlr = val & ICC_CTLR_EL1_CBPR_MASK;
-		vmcr.ctlr |= val & ICC_CTLR_EL1_EOImode_MASK;
+		vmcr.cbpr = (val & ICC_CTLR_EL1_CBPR_MASK) >> ICC_CTLR_EL1_CBPR_SHIFT;
+		vmcr.eoim = (val & ICC_CTLR_EL1_EOImode_MASK) >> ICC_CTLR_EL1_EOImode_SHIFT;
 		vgic_set_vmcr(vcpu, &vmcr);
 	} else {
 		val = 0;
@@ -83,8 +83,8 @@ static bool access_gic_ctlr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		 * The VMCR.CTLR value is in ICC_CTLR_EL1 layout.
 		 * Extract it directly using ICC_CTLR_EL1 reg definitions.
 		 */
-		val |= vmcr.ctlr & ICC_CTLR_EL1_CBPR_MASK;
-		val |= vmcr.ctlr & ICC_CTLR_EL1_EOImode_MASK;
+		val |= (vmcr.cbpr << ICC_CTLR_EL1_CBPR_SHIFT) & ICC_CTLR_EL1_CBPR_MASK;
+		val |= (vmcr.eoim << ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
 
 		p->regval = val;
 	}
@@ -135,7 +135,7 @@ static bool access_gic_bpr1(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		p->regval = 0;
 
 	vgic_get_vmcr(vcpu, &vmcr);
-	if (!((vmcr.ctlr & ICH_VMCR_CBPR_MASK) >> ICH_VMCR_CBPR_SHIFT)) {
+	if (!vmcr.cbpr) {
 		if (p->is_write) {
 			vmcr.abpr = (p->regval & ICC_BPR1_EL1_MASK) >>
 				     ICC_BPR1_EL1_SHIFT;
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index fffb912..1fa293a 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -417,6 +417,10 @@
 #define ICH_HCR_EN			(1 << 0)
 #define ICH_HCR_UIE			(1 << 1)
 
+#define ICH_VMCR_ACK_CTL_SHIFT		2
+#define ICH_VMCR_ACK_CTL_MASK		(1 << ICH_VMCR_ACK_CTL_SHIFT)
+#define ICH_VMCR_FIQ_EN_SHIFT		3
+#define ICH_VMCR_FIQ_EN_MASK		(1 << ICH_VMCR_FIQ_EN_SHIFT)
 #define ICH_VMCR_CBPR_SHIFT		4
 #define ICH_VMCR_CBPR_MASK		(1 << ICH_VMCR_CBPR_SHIFT)
 #define ICH_VMCR_EOIM_SHIFT		9
diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h
index dc30f3d..d3453ee 100644
--- a/include/linux/irqchip/arm-gic.h
+++ b/include/linux/irqchip/arm-gic.h
@@ -25,7 +25,18 @@
 #define GICC_ENABLE			0x1
 #define GICC_INT_PRI_THRESHOLD		0xf0
 
-#define GIC_CPU_CTRL_EOImodeNS		(1 << 9)
+#define GIC_CPU_CTRL_EnableGrp0_SHIFT	0
+#define GIC_CPU_CTRL_EnableGrp0		(1 << GIC_CPU_CTRL_EnableGrp0_SHIFT)
+#define GIC_CPU_CTRL_EnableGrp1_SHIFT	1
+#define GIC_CPU_CTRL_EnableGrp1		(1 << GIC_CPU_CTRL_EnableGrp1_SHIFT)
+#define GIC_CPU_CTRL_AckCtl_SHIFT	2
+#define GIC_CPU_CTRL_AckCtl		(1 << GIC_CPU_CTRL_AckCtl_SHIFT)
+#define GIC_CPU_CTRL_FIQEn_SHIFT	3
+#define GIC_CPU_CTRL_FIQEn		(1 << GIC_CPU_CTRL_FIQEn_SHIFT)
+#define GIC_CPU_CTRL_CBPR_SHIFT		4
+#define GIC_CPU_CTRL_CBPR		(1 << GIC_CPU_CTRL_CBPR_SHIFT)
+#define GIC_CPU_CTRL_EOImodeNS_SHIFT	9
+#define GIC_CPU_CTRL_EOImodeNS		(1 << GIC_CPU_CTRL_EOImodeNS_SHIFT)
 
 #define GICC_IAR_INT_ID_MASK		0x3ff
 #define GICC_INT_SPURIOUS		1023
@@ -84,8 +95,19 @@
 #define GICH_LR_EOI			(1 << 19)
 #define GICH_LR_HW			(1 << 31)
 
-#define GICH_VMCR_CTRL_SHIFT		0
-#define GICH_VMCR_CTRL_MASK		(0x21f << GICH_VMCR_CTRL_SHIFT)
+#define GICH_VMCR_ENABLE_GRP0_SHIFT	0
+#define GICH_VMCR_ENABLE_GRP0_MASK	(1 << GICH_VMCR_ENABLE_GRP0_SHIFT)
+#define GICH_VMCR_ENABLE_GRP1_SHIFT	1
+#define GICH_VMCR_ENABLE_GRP1_MASK	(1 << GICH_VMCR_ENABLE_GRP1_SHIFT)
+#define GICH_VMCR_ACK_CTL_SHIFT		2
+#define GICH_VMCR_ACK_CTL_MASK		(1 << GICH_VMCR_ACK_CTL_SHIFT)
+#define GICH_VMCR_FIQ_EN_SHIFT		3
+#define GICH_VMCR_FIQ_EN_MASK		(1 << GICH_VMCR_FIQ_EN_SHIFT)
+#define GICH_VMCR_CBPR_SHIFT		4
+#define GICH_VMCR_CBPR_MASK		(1 << GICH_VMCR_CBPR_SHIFT)
+#define GICH_VMCR_EOI_MODE_SHIFT	9
+#define GICH_VMCR_EOI_MODE_MASK		(1 << GICH_VMCR_EOI_MODE_SHIFT)
+
 #define GICH_VMCR_PRIMASK_SHIFT		27
 #define GICH_VMCR_PRIMASK_MASK		(0x1f << GICH_VMCR_PRIMASK_SHIFT)
 #define GICH_VMCR_BINPOINT_SHIFT	21
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v2.c b/virt/kvm/arm/vgic/vgic-mmio-v2.c
index 0a4283e..63e0bbd 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v2.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v2.c
@@ -226,7 +226,13 @@ static unsigned long vgic_mmio_read_vcpuif(struct kvm_vcpu *vcpu,
 
 	switch (addr & 0xff) {
 	case GIC_CPU_CTRL:
-		val = vmcr.ctlr;
+		val = vmcr.grpen0 << GIC_CPU_CTRL_EnableGrp0_SHIFT;
+		val |= vmcr.grpen1 << GIC_CPU_CTRL_EnableGrp1_SHIFT;
+		val |= vmcr.ackctl << GIC_CPU_CTRL_AckCtl_SHIFT;
+		val |= vmcr.fiqen << GIC_CPU_CTRL_FIQEn_SHIFT;
+		val |= vmcr.cbpr << GIC_CPU_CTRL_CBPR_SHIFT;
+		val |= vmcr.eoim << GIC_CPU_CTRL_EOImodeNS_SHIFT;
+
 		break;
 	case GIC_CPU_PRIMASK:
 		/*
@@ -267,7 +273,13 @@ static void vgic_mmio_write_vcpuif(struct kvm_vcpu *vcpu,
 
 	switch (addr & 0xff) {
 	case GIC_CPU_CTRL:
-		vmcr.ctlr = val;
+		vmcr.grpen0 = !!(val & GIC_CPU_CTRL_EnableGrp0);
+		vmcr.grpen1 = !!(val & GIC_CPU_CTRL_EnableGrp1);
+		vmcr.ackctl = !!(val & GIC_CPU_CTRL_AckCtl);
+		vmcr.fiqen = !!(val & GIC_CPU_CTRL_FIQEn);
+		vmcr.cbpr = !!(val & GIC_CPU_CTRL_CBPR);
+		vmcr.eoim = !!(val & GIC_CPU_CTRL_EOImodeNS);
+
 		break;
 	case GIC_CPU_PRIMASK:
 		/*
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index 504b4bd..e4187e5 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -177,7 +177,18 @@ void vgic_v2_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 	struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
 	u32 vmcr;
 
-	vmcr  = (vmcrp->ctlr << GICH_VMCR_CTRL_SHIFT) & GICH_VMCR_CTRL_MASK;
+	vmcr = (vmcrp->grpen0 << GICH_VMCR_ENABLE_GRP0_SHIFT) &
+		GICH_VMCR_ENABLE_GRP0_MASK;
+	vmcr |= (vmcrp->grpen1 << GICH_VMCR_ENABLE_GRP1_SHIFT) &
+		GICH_VMCR_ENABLE_GRP1_MASK;
+	vmcr |= (vmcrp->ackctl << GICH_VMCR_ACK_CTL_SHIFT) &
+		GICH_VMCR_ACK_CTL_MASK;
+	vmcr |= (vmcrp->fiqen << GICH_VMCR_FIQ_EN_SHIFT) &
+		GICH_VMCR_FIQ_EN_MASK;
+	vmcr |= (vmcrp->cbpr << GICH_VMCR_CBPR_SHIFT) &
+		GICH_VMCR_CBPR_MASK;
+	vmcr |= (vmcrp->eoim << GICH_VMCR_EOI_MODE_SHIFT) &
+		GICH_VMCR_EOI_MODE_MASK;
 	vmcr |= (vmcrp->abpr << GICH_VMCR_ALIAS_BINPOINT_SHIFT) &
 		GICH_VMCR_ALIAS_BINPOINT_MASK;
 	vmcr |= (vmcrp->bpr << GICH_VMCR_BINPOINT_SHIFT) &
@@ -195,8 +206,19 @@ void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 
 	vmcr = cpu_if->vgic_vmcr;
 
-	vmcrp->ctlr = (vmcr & GICH_VMCR_CTRL_MASK) >>
-			GICH_VMCR_CTRL_SHIFT;
+	vmcrp->grpen0 = (vmcr & GICH_VMCR_ENABLE_GRP0_MASK) >>
+		GICH_VMCR_ENABLE_GRP0_SHIFT;
+	vmcrp->grpen1 = (vmcr & GICH_VMCR_ENABLE_GRP1_MASK) >>
+		GICH_VMCR_ENABLE_GRP1_SHIFT;
+	vmcrp->ackctl = (vmcr & GICH_VMCR_ACK_CTL_MASK) >>
+		GICH_VMCR_ACK_CTL_SHIFT;
+	vmcrp->fiqen = (vmcr & GICH_VMCR_FIQ_EN_MASK) >>
+		GICH_VMCR_FIQ_EN_SHIFT;
+	vmcrp->cbpr = (vmcr & GICH_VMCR_CBPR_MASK) >>
+		GICH_VMCR_CBPR_SHIFT;
+	vmcrp->eoim = (vmcr & GICH_VMCR_EOI_MODE_MASK) >>
+		GICH_VMCR_EOI_MODE_SHIFT;
+
 	vmcrp->abpr = (vmcr & GICH_VMCR_ALIAS_BINPOINT_MASK) >>
 			GICH_VMCR_ALIAS_BINPOINT_SHIFT;
 	vmcrp->bpr  = (vmcr & GICH_VMCR_BINPOINT_MASK) >>
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 6fe3f00..030248e 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -159,15 +159,24 @@ void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr)
 void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 {
 	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+	u32 model = vcpu->kvm->arch.vgic.vgic_model;
 	u32 vmcr;
 
-	/*
-	 * Ignore the FIQen bit, because GIC emulation always implies
-	 * SRE=1 which means the vFIQEn bit is also RES1.
-	 */
-	vmcr = ((vmcrp->ctlr >> ICC_CTLR_EL1_EOImode_SHIFT) <<
-		 ICH_VMCR_EOIM_SHIFT) & ICH_VMCR_EOIM_MASK;
-	vmcr |= (vmcrp->ctlr << ICH_VMCR_CBPR_SHIFT) & ICH_VMCR_CBPR_MASK;
+	if (model == KVM_DEV_TYPE_ARM_VGIC_V2) {
+		vmcr = (vmcrp->ackctl << ICH_VMCR_ACK_CTL_SHIFT) &
+			ICH_VMCR_ACK_CTL_MASK;
+		vmcr |= (vmcrp->fiqen << ICH_VMCR_FIQ_EN_SHIFT) &
+			ICH_VMCR_FIQ_EN_MASK;
+	} else {
+		/*
+		 * When emulating GICv3 on GICv3 with SRE=1 on the
+		 * VFIQEn bit is RES1 and the VAckCtl bit is RES0.
+		 */
+		vmcr = ICH_VMCR_FIQ_EN_MASK;
+	}
+
+	vmcr |= (vmcrp->cbpr << ICH_VMCR_CBPR_SHIFT) & ICH_VMCR_CBPR_MASK;
+	vmcr |= (vmcrp->eoim << ICH_VMCR_EOIM_SHIFT) & ICH_VMCR_EOIM_MASK;
 	vmcr |= (vmcrp->abpr << ICH_VMCR_BPR1_SHIFT) & ICH_VMCR_BPR1_MASK;
 	vmcr |= (vmcrp->bpr << ICH_VMCR_BPR0_SHIFT) & ICH_VMCR_BPR0_MASK;
 	vmcr |= (vmcrp->pmr << ICH_VMCR_PMR_SHIFT) & ICH_VMCR_PMR_MASK;
@@ -180,17 +189,27 @@ void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 {
 	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+	u32 model = vcpu->kvm->arch.vgic.vgic_model;
 	u32 vmcr;
 
 	vmcr = cpu_if->vgic_vmcr;
 
-	/*
-	 * Ignore the FIQen bit, because GIC emulation always implies
-	 * SRE=1 which means the vFIQEn bit is also RES1.
-	 */
-	vmcrp->ctlr = ((vmcr >> ICH_VMCR_EOIM_SHIFT) <<
-			ICC_CTLR_EL1_EOImode_SHIFT) & ICC_CTLR_EL1_EOImode_MASK;
-	vmcrp->ctlr |= (vmcr & ICH_VMCR_CBPR_MASK) >> ICH_VMCR_CBPR_SHIFT;
+	if (model == KVM_DEV_TYPE_ARM_VGIC_V2) {
+		vmcrp->ackctl = (vmcr & ICH_VMCR_ACK_CTL_MASK) >>
+			ICH_VMCR_ACK_CTL_SHIFT;
+		vmcrp->fiqen = (vmcr & ICH_VMCR_FIQ_EN_MASK) >>
+			ICH_VMCR_FIQ_EN_SHIFT;
+	} else {
+		/*
+		 * When emulating GICv3 on GICv3 with SRE=1 on the
+		 * VFIQEn bit is RES1 and the VAckCtl bit is RES0.
+		 */
+		vmcrp->fiqen = 1;
+		vmcrp->ackctl = 0;
+	}
+
+	vmcrp->cbpr = (vmcr & ICH_VMCR_CBPR_MASK) >> ICH_VMCR_CBPR_SHIFT;
+	vmcrp->eoim = (vmcr & ICH_VMCR_EOIM_MASK) >> ICH_VMCR_EOIM_SHIFT;
 	vmcrp->abpr = (vmcr & ICH_VMCR_BPR1_MASK) >> ICH_VMCR_BPR1_SHIFT;
 	vmcrp->bpr  = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;
 	vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index da83e4c..bba7fa2 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -111,14 +111,18 @@ static inline bool irq_is_pending(struct vgic_irq *irq)
  * registers regardless of the hardware backed GIC used.
  */
 struct vgic_vmcr {
-	u32	ctlr;
+	u32	grpen0;
+	u32	grpen1;
+
+	u32	ackctl;
+	u32	fiqen;
+	u32	cbpr;
+	u32	eoim;
+
 	u32	abpr;
 	u32	bpr;
 	u32	pmr;  /* Priority mask field in the GICC_PMR and
 		       * ICC_PMR_EL1 priority field format */
-	/* Below member variable are valid only for GICv3 */
-	u32	grpen0;
-	u32	grpen1;
 };
 
 struct vgic_reg_attr {
-- 
2.9.0

[PULL v2 2/6] KVM: arm/arm64: vgic-v3: Fix nr_pre_bits bitfield extraction

[Christoffer Dall]

We used to extract PRIbits from the ICH_VT_EL2 which was the upper field
in the register word, so a mask wasn't necessary, but as we switched to
looking at PREbits, which is bits 26 through 28 with the PRIbits field
being potentially non-zero, we really need to mask off the field value,
otherwise fun things may happen.

Signed-off-by: Christoffer Dall <cdall@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
---
 virt/kvm/arm/hyp/vgic-v3-sr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
index 32c3295..8794036 100644
--- a/virt/kvm/arm/hyp/vgic-v3-sr.c
+++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
@@ -22,7 +22,7 @@
 #include <asm/kvm_hyp.h>
 
 #define vtr_to_max_lr_idx(v)		((v) & 0xf)
-#define vtr_to_nr_pre_bits(v)		(((u32)(v) >> 26) + 1)
+#define vtr_to_nr_pre_bits(v)		((((u32)(v) >> 26) & 7) + 1)
 
 static u64 __hyp_text __gic_v3_get_lr(unsigned int lr)
 {
-- 
2.9.0

[PULL v2 3/6] KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

Under memory pressure, we start ageing pages, which amounts to parsing
the page tables. Since we don't want to allocate any extra level,
we pass NULL for our private allocation cache. Which means that
stage2_get_pud() is allowed to fail. This results in the following
splat:

[ 1520.409577] Unable to handle kernel NULL pointer dereference at virtual address 00000008
[ 1520.417741] pgd = ffff810f52fef000
[ 1520.421201] [00000008] *pgd=0000010f636c5003, *pud=0000010f56f48003, *pmd=0000000000000000
[ 1520.429546] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[ 1520.435156] Modules linked in:
[ 1520.438246] CPU: 15 PID: 53550 Comm: qemu-system-aar Tainted: G        W       4.12.0-rc4-00027-g1885c397eaec #7205
[ 1520.448705] Hardware name: FOXCONN R2-1221R-A4/C2U4N_MB, BIOS G31FB12A 10/26/2016
[ 1520.463726] task: ffff800ac5fb4e00 task.stack: ffff800ce04e0000
[ 1520.469666] PC is at stage2_get_pmd+0x34/0x110
[ 1520.474119] LR is at kvm_age_hva_handler+0x44/0xf0
[ 1520.478917] pc : [<ffff0000080b137c>] lr : [<ffff0000080b149c>] pstate: 40000145
[ 1520.486325] sp : ffff800ce04e33d0
[ 1520.489644] x29: ffff800ce04e33d0 x28: 0000000ffff40064
[ 1520.494967] x27: 0000ffff27e00000 x26: 0000000000000000
[ 1520.500289] x25: ffff81051ba65008 x24: 0000ffff40065000
[ 1520.505618] x23: 0000ffff40064000 x22: 0000000000000000
[ 1520.510947] x21: ffff810f52b20000 x20: 0000000000000000
[ 1520.516274] x19: 0000000058264000 x18: 0000000000000000
[ 1520.521603] x17: 0000ffffa6fe7438 x16: ffff000008278b70
[ 1520.526940] x15: 000028ccd8000000 x14: 0000000000000008
[ 1520.532264] x13: ffff7e0018298000 x12: 0000000000000002
[ 1520.537582] x11: ffff000009241b93 x10: 0000000000000940
[ 1520.542908] x9 : ffff0000092ef800 x8 : 0000000000000200
[ 1520.548229] x7 : ffff800ce04e36a8 x6 : 0000000000000000
[ 1520.553552] x5 : 0000000000000001 x4 : 0000000000000000
[ 1520.558873] x3 : 0000000000000000 x2 : 0000000000000008
[ 1520.571696] x1 : ffff000008fd5000 x0 : ffff0000080b149c
[ 1520.577039] Process qemu-system-aar (pid: 53550, stack limit = 0xffff800ce04e0000)
[...]
[ 1521.510735] [<ffff0000080b137c>] stage2_get_pmd+0x34/0x110
[ 1521.516221] [<ffff0000080b149c>] kvm_age_hva_handler+0x44/0xf0
[ 1521.522054] [<ffff0000080b0610>] handle_hva_to_gpa+0xb8/0xe8
[ 1521.527716] [<ffff0000080b3434>] kvm_age_hva+0x44/0xf0
[ 1521.532854] [<ffff0000080a58b0>] kvm_mmu_notifier_clear_flush_young+0x70/0xc0
[ 1521.539992] [<ffff000008238378>] __mmu_notifier_clear_flush_young+0x88/0xd0
[ 1521.546958] [<ffff00000821eca0>] page_referenced_one+0xf0/0x188
[ 1521.552881] [<ffff00000821f36c>] rmap_walk_anon+0xec/0x250
[ 1521.558370] [<ffff000008220f78>] rmap_walk+0x78/0xa0
[ 1521.563337] [<ffff000008221104>] page_referenced+0x164/0x180
[ 1521.569002] [<ffff0000081f1af0>] shrink_active_list+0x178/0x3b8
[ 1521.574922] [<ffff0000081f2058>] shrink_node_memcg+0x328/0x600
[ 1521.580758] [<ffff0000081f23f4>] shrink_node+0xc4/0x328
[ 1521.585986] [<ffff0000081f2718>] do_try_to_free_pages+0xc0/0x340
[ 1521.592000] [<ffff0000081f2a64>] try_to_free_pages+0xcc/0x240
[...]

The trivial fix is to handle this NULL pud value early, rather than
dereferencing it blindly.

Cc: stable at vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
 virt/kvm/arm/mmu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index a2d6324..e2e5eff 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -879,6 +879,9 @@ static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache
 	pmd_t *pmd;
 
 	pud = stage2_get_pud(kvm, cache, addr);
+	if (!pud)
+		return NULL;
+
 	if (stage2_pud_none(*pud)) {
 		if (!cache)
 			return NULL;
-- 
2.9.0

[PULL v2 4/6] arm64: KVM: Preserve RES1 bits in SCTLR_EL2

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

__do_hyp_init has the rather bad habit of ignoring RES1 bits and
writing them back as zero. On a v8.0-8.2 CPU, this doesn't do anything
bad, but may end-up being pretty nasty on future revisions of the
architecture.

Let's preserve those bits so that we don't have to fix this later on.

Cc: stable at vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
 arch/arm64/include/asm/sysreg.h |  4 ++++
 arch/arm64/kvm/hyp-init.S       | 10 ++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 15c142c..b4d13d9 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -286,6 +286,10 @@
 #define SCTLR_ELx_A	(1 << 1)
 #define SCTLR_ELx_M	1
 
+#define SCTLR_EL2_RES1	((1 << 4)  | (1 << 5)  | (1 << 11) | (1 << 16) | \
+			 (1 << 16) | (1 << 18) | (1 << 22) | (1 << 23) | \
+			 (1 << 28) | (1 << 29))
+
 #define SCTLR_ELx_FLAGS	(SCTLR_ELx_M | SCTLR_ELx_A | SCTLR_ELx_C | \
 			 SCTLR_ELx_SA | SCTLR_ELx_I)
 
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 839425c..4072d40 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -106,10 +106,12 @@ __do_hyp_init:
 	tlbi	alle2
 	dsb	sy
 
-	mrs	x4, sctlr_el2
-	and	x4, x4, #SCTLR_ELx_EE	// preserve endianness of EL2
-	ldr	x5, =SCTLR_ELx_FLAGS
-	orr	x4, x4, x5
+	/*
+	 * Preserve all the RES1 bits while setting the default flags,
+	 * as well as the EE bit on BE.
+	 */
+	ldr	x4, =(SCTLR_EL2_RES1 | SCTLR_ELx_FLAGS)
+CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
 	msr	sctlr_el2, x4
 	isb
 
-- 
2.9.0

[PULL v2 5/6] arm64: KVM: Allow unaligned accesses at EL2

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

We currently have the SCTLR_EL2.A bit set, trapping unaligned accesses
at EL2, but we're not really prepared to deal with it. So far, this
has been unnoticed, until GCC 7 started emitting those (in particular
64bit writes on a 32bit boundary).

Since the rest of the kernel is pretty happy about that, let's follow
its example and set SCTLR_EL2.A to zero. Modern CPUs don't really
care.

Cc: stable at vger.kernel.org
Reported-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
 arch/arm64/kvm/hyp-init.S | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 4072d40..3f96155 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -108,9 +108,10 @@ __do_hyp_init:
 
 	/*
 	 * Preserve all the RES1 bits while setting the default flags,
-	 * as well as the EE bit on BE.
+	 * as well as the EE bit on BE. Drop the A flag since the compiler
+	 * is allowed to generate unaligned accesses.
 	 */
-	ldr	x4, =(SCTLR_EL2_RES1 | SCTLR_ELx_FLAGS)
+	ldr	x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
 CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
 	msr	sctlr_el2, x4
 	isb
-- 
2.9.0

[PULL v2 6/6] arm: KVM: Allow unaligned accesses at HYP

[Christoffer Dall]

From: Marc Zyngier <marc.zyngier@arm.com>

We currently have the HSCTLR.A bit set, trapping unaligned accesses
at HYP, but we're not really prepared to deal with it.

Since the rest of the kernel is pretty happy about that, let's follow
its example and set HSCTLR.A to zero. Modern CPUs don't really care.

Cc: stable at vger.kernel.org
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
---
 arch/arm/kvm/init.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S
index 570ed4a..5386528 100644
--- a/arch/arm/kvm/init.S
+++ b/arch/arm/kvm/init.S
@@ -104,7 +104,6 @@ __do_hyp_init:
 	@  - Write permission implies XN: disabled
 	@  - Instruction cache: enabled
 	@  - Data/Unified cache: enabled
-	@  - Memory alignment checks: enabled
 	@  - MMU: enabled (this code must be run from an identity mapping)
 	mrc	p15, 4, r0, c1, c0, 0	@ HSCR
 	ldr	r2, =HSCTLR_MASK
@@ -112,8 +111,8 @@ __do_hyp_init:
 	mrc	p15, 0, r1, c1, c0, 0	@ SCTLR
 	ldr	r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C)
 	and	r1, r1, r2
- ARM(	ldr	r2, =(HSCTLR_M | HSCTLR_A)			)
- THUMB(	ldr	r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE)		)
+ ARM(	ldr	r2, =(HSCTLR_M)					)
+ THUMB(	ldr	r2, =(HSCTLR_M | HSCTLR_TE)			)
 	orr	r1, r1, r2
 	orr	r0, r0, r1
 	mcr	p15, 4, r0, c1, c0, 0	@ HSCR
-- 
2.9.0

[PULL v2 0/6] KVM/ARM Fixes for v4.12-rc5 - Take 2

[Paolo Bonzini]

On 07/06/2017 19:11, Christoffer Dall wrote:
> Hi Radim and Paolo,
> 
> Six additional fixes for KVM/ARM for v4.12 (instead of only the first
> three in the first version of this pull request).
> 
> The changes are:
>  - Fix an issue with migrating GICv2 VMs on GICv3 systems.
>  - Squashed a bug for gicv3 when figuring out preemption levels.
>  - Fix a potential null pointer derefence in KVM happening under memory
>    pressure.
>  - Maintain RES1 bits in the SCTLR_EL2 to make sure KVM works on new
>    architecture revisions.
>  - Allow unaligned accesses at EL2/HYP
> 
> The following changes since commit fa472fa91a5a0b241f5ddae927d2e235d07545df:
> 
>   KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices (2017-05-18 11:18:16 +0200)
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git kvm-arm-for-v4.12-rc5-take2
> 
> for you to fetch changes up to 33b5c38852b29736f3b472dd095c9a18ec22746f:
> 
>   arm: KVM: Allow unaligned accesses at HYP (2017-06-06 22:20:02 +0200)
> 
> Thanks,
> -Christoffer

Pulled, thanks.

Paolo

> ---
> Christoffer Dall (2):
>       KVM: arm/arm64: Fix isues with GICv2 on GICv3 migration
>       KVM: arm/arm64: vgic-v3: Fix nr_pre_bits bitfield extraction
> 
> Marc Zyngier (4):
>       KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages
>       arm64: KVM: Preserve RES1 bits in SCTLR_EL2
>       arm64: KVM: Allow unaligned accesses at EL2
>       arm: KVM: Allow unaligned accesses at HYP
> 
>  arch/arm/kvm/init.S                |  5 ++--
>  arch/arm64/include/asm/sysreg.h    |  4 ++++
>  arch/arm64/kvm/hyp-init.S          | 11 +++++----
>  arch/arm64/kvm/vgic-sys-reg-v3.c   | 10 ++++----
>  include/linux/irqchip/arm-gic-v3.h |  4 ++++
>  include/linux/irqchip/arm-gic.h    | 28 ++++++++++++++++++++---
>  virt/kvm/arm/hyp/vgic-v3-sr.c      |  2 +-
>  virt/kvm/arm/mmu.c                 |  3 +++
>  virt/kvm/arm/vgic/vgic-mmio-v2.c   | 16 +++++++++++--
>  virt/kvm/arm/vgic/vgic-v2.c        | 28 ++++++++++++++++++++---
>  virt/kvm/arm/vgic/vgic-v3.c        | 47 ++++++++++++++++++++++++++------------
>  virt/kvm/arm/vgic/vgic.h           | 12 ++++++----
>  12 files changed, 131 insertions(+), 39 deletions(-)
>