[PATCH 4.4-stable 0/2] arm64: KVM: PSTATE.M sanitization

[PATCH 4.4-stable 0/2] arm64: KVM: PSTATE.M sanitization

[Marc Zyngier]

This is a backport of 2a3f93459d689d990b3ecfbe782fec89b97d3279
("arm64: KVM: Sanitize PSTATE.M when being set from userspace") to
4.4-stable.

It requires a backport of 042446a31e3803d81c7e618dd80928dc3dce70c5
("arm64: cpufeature: Track 32bit EL0 support") as a dependency.

Marc Zyngier (1):
  arm64: KVM: Sanitize PSTATE.M when being set from userspace

Suzuki K Poulose (1):
  arm64: cpufeature: Track 32bit EL0 support

 arch/arm64/include/asm/cpufeature.h  |  8 +++++++-
 arch/arm64/include/asm/kvm_emulate.h |  5 +++++
 arch/arm64/include/asm/sysreg.h      |  1 +
 arch/arm64/kernel/cpufeature.c       |  8 ++++++++
 arch/arm64/kvm/guest.c               | 10 +++++++++-
 5 files changed, 30 insertions(+), 2 deletions(-)

-- 
2.19.0

[PATCH 4.4-stable 1/2] arm64: cpufeature: Track 32bit EL0 support

[Marc Zyngier]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

commit 042446a31e3803d81c7e618dd80928dc3dce70c5 upstream.

Add cpu_hwcap bit for keeping track of the support for 32bit EL0.

Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/cpufeature.h | 8 +++++++-
 arch/arm64/include/asm/sysreg.h     | 1 +
 arch/arm64/kernel/cpufeature.c      | 8 ++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 8884b5d5f48c..ad83c245781c 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -31,8 +31,9 @@
 #define ARM64_WORKAROUND_CAVIUM_23154		6
 #define ARM64_WORKAROUND_834220			7
 #define ARM64_WORKAROUND_CAVIUM_27456		8
+#define ARM64_HAS_32BIT_EL0			9
 
-#define ARM64_NCAPS				9
+#define ARM64_NCAPS				10
 
 #ifndef __ASSEMBLY__
 
@@ -180,6 +181,11 @@ static inline bool cpu_supports_mixed_endian_el0(void)
 	return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
 }
 
+static inline bool system_supports_32bit_el0(void)
+{
+	return cpus_have_cap(ARM64_HAS_32BIT_EL0);
+}
+
 static inline bool system_supports_mixed_endian_el0(void)
 {
 	return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index d48ab5b41f52..50150320f80d 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -109,6 +109,7 @@
 #define ID_AA64PFR0_ASIMD_SUPPORTED	0x0
 #define ID_AA64PFR0_EL1_64BIT_ONLY	0x1
 #define ID_AA64PFR0_EL0_64BIT_ONLY	0x1
+#define ID_AA64PFR0_EL0_32BIT_64BIT	0x2
 
 /* id_aa64mmfr0 */
 #define ID_AA64MMFR0_TGRAN4_SHIFT	28
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 2735bf814592..c1eddc07d996 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -653,6 +653,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.min_field_value = 2,
 	},
 #endif /* CONFIG_AS_LSE && CONFIG_ARM64_LSE_ATOMICS */
+	{
+		.desc = "32-bit EL0 Support",
+		.capability = ARM64_HAS_32BIT_EL0,
+		.matches = has_cpuid_feature,
+		.sys_reg = SYS_ID_AA64PFR0_EL1,
+		.field_pos = ID_AA64PFR0_EL0_SHIFT,
+		.min_field_value = ID_AA64PFR0_EL0_32BIT_64BIT,
+	},
 	{},
 };
 
-- 
2.19.0

[PATCH 4.4-stable 2/2] arm64: KVM: Sanitize PSTATE.M when being set from userspace

[Marc Zyngier]

commit 2a3f93459d689d990b3ecfbe782fec89b97d3279 upstream.

Not all execution modes are valid for a guest, and some of them
depend on what the HW actually supports. Let's verify that what
userspace provides is compatible with both the VM settings and
the HW capabilities.

Cc: <stable@vger.kernel.org>
Fixes: 0d854a60b1d7 ("arm64: KVM: enable initialization of a 32bit vcpu")
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/kvm_emulate.h |  5 +++++
 arch/arm64/kvm/guest.c               | 10 +++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 25a40213bd9b..0729a2f94482 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -41,6 +41,11 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu);
 void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
 void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
 
+static inline bool vcpu_el1_is_32bit(struct kvm_vcpu *vcpu)
+{
+	return !(vcpu->arch.hcr_el2 & HCR_RW);
+}
+
 static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 83aa598ed81e..79705fde8cc8 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -143,17 +143,25 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	}
 
 	if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) {
-		u32 mode = (*(u32 *)valp) & COMPAT_PSR_MODE_MASK;
+		u64 mode = (*(u64 *)valp) & COMPAT_PSR_MODE_MASK;
 		switch (mode) {
 		case COMPAT_PSR_MODE_USR:
+			if (!system_supports_32bit_el0())
+				return -EINVAL;
+			break;
 		case COMPAT_PSR_MODE_FIQ:
 		case COMPAT_PSR_MODE_IRQ:
 		case COMPAT_PSR_MODE_SVC:
 		case COMPAT_PSR_MODE_ABT:
 		case COMPAT_PSR_MODE_UND:
+			if (!vcpu_el1_is_32bit(vcpu))
+				return -EINVAL;
+			break;
 		case PSR_MODE_EL0t:
 		case PSR_MODE_EL1t:
 		case PSR_MODE_EL1h:
+			if (vcpu_el1_is_32bit(vcpu))
+				return -EINVAL;
 			break;
 		default:
 			err = -EINVAL;
-- 
2.19.0

Re: [PATCH 4.4-stable 0/2] arm64: KVM: PSTATE.M sanitization

[Greg KH]

On Tue, Oct 02, 2018 at 04:04:03PM +0100, Marc Zyngier wrote:
> This is a backport of 2a3f93459d689d990b3ecfbe782fec89b97d3279
> ("arm64: KVM: Sanitize PSTATE.M when being set from userspace") to
> 4.4-stable.
> 
> It requires a backport of 042446a31e3803d81c7e618dd80928dc3dce70c5
> ("arm64: cpufeature: Track 32bit EL0 support") as a dependency.

All now queued up, thanks.

greg k-h