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 865a7e28ea2d..3d0098d7b47e 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -38,6 +38,11 @@ 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 5d93c9f24847..286453f462df 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -141,17 +141,25 @@ 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 ((read_cpuid(ID_AA64PFR0_EL1) & 0xf) != 2) + 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;