From 488f94d7212b00a2ec72fb886b155f1b04c5aa98 Mon Sep 17 00:00:00 2001 From: Jintack Lim Date: Thu, 1 Dec 2016 14:32:05 -0500 Subject: KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems Current KVM world switch code is unintentionally setting wrong bits to CNTHCTL_EL2 when E2H == 1, which may allow guest OS to access physical timer. Bit positions of CNTHCTL_EL2 are changing depending on HCR_EL2.E2H bit. EL1PCEN and EL1PCTEN are 1st and 0th bits when E2H is not set, but they are 11th and 10th bits respectively when E2H is set. In fact, on VHE we only need to set those bits once, not for every world switch. This is because the host kernel runs in EL2 with HCR_EL2.TGE == 1, which makes those bits have no effect for the host kernel execution. So we just set those bits once for guests, and that's it. Signed-off-by: Jintack Lim Reviewed-by: Marc Zyngier Signed-off-by: Marc Zyngier --- arch/arm/include/asm/virt.h | 5 +++++ arch/arm/kvm/arm.c | 3 +++ arch/arm64/include/asm/virt.h | 9 +++++++++ 3 files changed, 17 insertions(+) (limited to 'arch') diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h index a2e75b84e2ae..6dae1956c74d 100644 --- a/arch/arm/include/asm/virt.h +++ b/arch/arm/include/asm/virt.h @@ -80,6 +80,11 @@ static inline bool is_kernel_in_hyp_mode(void) return false; } +static inline bool has_vhe(void) +{ + return false; +} + /* The section containing the hypervisor idmap text */ extern char __hyp_idmap_text_start[]; extern char __hyp_idmap_text_end[]; diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 11676787ad49..9d7446456e0c 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -1099,6 +1099,9 @@ static void cpu_init_hyp_mode(void *dummy) __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr); __cpu_init_stage2(); + if (is_kernel_in_hyp_mode()) + kvm_timer_init_vhe(); + kvm_arm_init_debug(); } diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index fea10736b11f..439f6b5d31f6 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -47,6 +47,7 @@ #include #include #include +#include /* * __boot_cpu_mode records what mode CPUs were booted in. @@ -80,6 +81,14 @@ static inline bool is_kernel_in_hyp_mode(void) return read_sysreg(CurrentEL) == CurrentEL_EL2; } +static inline bool has_vhe(void) +{ + if (cpus_have_const_cap(ARM64_HAS_VIRT_HOST_EXTN)) + return true; + + return false; +} + #ifdef CONFIG_ARM64_VHE extern void verify_cpu_run_el(void); #else -- cgit v1.2.3 From ce2e852ecc9a42e4b8dabb46025cfef63209234a Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Tue, 17 Jan 2017 14:51:04 +0100 Subject: KVM: x86: fix fixing of hypercalls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit emulator_fix_hypercall() replaces hypercall with vmcall instruction, but it does not handle GP exception properly when writes the new instruction. It can return X86EMUL_PROPAGATE_FAULT without setting exception information. This leads to incorrect emulation and triggers WARN_ON(ctxt->exception.vector > 0x1f) in x86_emulate_insn() as discovered by syzkaller fuzzer: WARNING: CPU: 2 PID: 18646 at arch/x86/kvm/emulate.c:5558 Call Trace: warn_slowpath_null+0x2c/0x40 kernel/panic.c:582 x86_emulate_insn+0x16a5/0x4090 arch/x86/kvm/emulate.c:5572 x86_emulate_instruction+0x403/0x1cc0 arch/x86/kvm/x86.c:5618 emulate_instruction arch/x86/include/asm/kvm_host.h:1127 [inline] handle_exception+0x594/0xfd0 arch/x86/kvm/vmx.c:5762 vmx_handle_exit+0x2b7/0x38b0 arch/x86/kvm/vmx.c:8625 vcpu_enter_guest arch/x86/kvm/x86.c:6888 [inline] vcpu_run arch/x86/kvm/x86.c:6947 [inline] Set exception information when write in emulator_fix_hypercall() fails. Signed-off-by: Dmitry Vyukov Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Wanpeng Li Cc: kvm@vger.kernel.org Cc: syzkaller@googlegroups.com Signed-off-by: Radim Krčmář --- arch/x86/kvm/x86.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 57d8a856cdc5..d153be8929a6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6171,7 +6171,8 @@ static int emulator_fix_hypercall(struct x86_emulate_ctxt *ctxt) kvm_x86_ops->patch_hypercall(vcpu, instruction); - return emulator_write_emulated(ctxt, rip, instruction, 3, NULL); + return emulator_write_emulated(ctxt, rip, instruction, 3, + &ctxt->exception); } static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From 04478197416e3a302e9ebc917ba1aa884ef9bfab Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Thu, 12 Jan 2017 16:25:15 +0100 Subject: KVM: s390: do not expose random data via facility bitmap kvm_s390_get_machine() populates the facility bitmap by copying bytes from the host results that are stored in a 256 byte array in the prefix page. The KVM code does use the size of the target buffer (2k), thus copying and exposing unrelated kernel memory (mostly machine check related logout data). Let's use the size of the source buffer instead. This is ok, as the target buffer will always be greater or equal than the source buffer as the KVM internal buffers (and thus S390_ARCH_FAC_LIST_SIZE_BYTE) cover the maximum possible size that is allowed by STFLE, which is 256 doublewords. All structures are zero allocated so we can leave bytes 256-2047 unchanged. Add a similar fix for kvm_arch_init_vm(). Reported-by: Heiko Carstens [found with smatch] Signed-off-by: Christian Borntraeger CC: stable@vger.kernel.org Acked-by: Cornelia Huck --- arch/s390/kvm/kvm-s390.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index bec71e902be3..6484a250021e 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -916,7 +916,7 @@ static int kvm_s390_get_machine(struct kvm *kvm, struct kvm_device_attr *attr) memcpy(&mach->fac_mask, kvm->arch.model.fac_mask, S390_ARCH_FAC_LIST_SIZE_BYTE); memcpy((unsigned long *)&mach->fac_list, S390_lowcore.stfle_fac_list, - S390_ARCH_FAC_LIST_SIZE_BYTE); + sizeof(S390_lowcore.stfle_fac_list)); if (copy_to_user((void __user *)attr->addr, mach, sizeof(*mach))) ret = -EFAULT; kfree(mach); @@ -1437,7 +1437,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) /* Populate the facility mask initially. */ memcpy(kvm->arch.model.fac_mask, S390_lowcore.stfle_fac_list, - S390_ARCH_FAC_LIST_SIZE_BYTE); + sizeof(S390_lowcore.stfle_fac_list)); for (i = 0; i < S390_ARCH_FAC_LIST_SIZE_U64; i++) { if (i < kvm_s390_fac_list_mask_size()) kvm->arch.model.fac_mask[i] &= kvm_s390_fac_list_mask[i]; -- cgit v1.2.3