From 8fc153cda9c9e6aed2a4a7235970dd6c6cb6e954 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 6 Jan 2016 18:29:19 +0000 Subject: arm64: KVM: Fix AArch64 guest userspace exception injection At the moment, our fault injection is pretty limited. We always generate a SYNC exception into EL1, as if the fault was actually from EL1h, no matter how it was generated. This is obviously wrong, as EL0 can generate faults of its own (not to mention the pretty-much unused EL1t mode). This patch fixes it by implementing section D1.10.2 of the ARMv8 ARM, and in particular table D1-7 ("Vector offsets from vector table base address"), which describes which vector to use depending on the source exception level and type (synchronous, IRQ, FIQ or SError). Reviewed-by: Christoffer Dall Tested-by: Shannon Zhao Signed-off-by: Marc Zyngier --- arch/arm64/kvm/inject_fault.c | 38 +++++++++++++++++++++++++++++++++++--- 1 file changed, 35 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c index 648112e90ed5..4d1ac81870d2 100644 --- a/arch/arm64/kvm/inject_fault.c +++ b/arch/arm64/kvm/inject_fault.c @@ -27,7 +27,11 @@ #define PSTATE_FAULT_BITS_64 (PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \ PSR_I_BIT | PSR_D_BIT) -#define EL1_EXCEPT_SYNC_OFFSET 0x200 + +#define CURRENT_EL_SP_EL0_VECTOR 0x0 +#define CURRENT_EL_SP_ELx_VECTOR 0x200 +#define LOWER_EL_AArch64_VECTOR 0x400 +#define LOWER_EL_AArch32_VECTOR 0x600 static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset) { @@ -97,6 +101,34 @@ static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt, *fsr = 0x14; } +enum exception_type { + except_type_sync = 0, + except_type_irq = 0x80, + except_type_fiq = 0x100, + except_type_serror = 0x180, +}; + +static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type) +{ + u64 exc_offset; + + switch (*vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT)) { + case PSR_MODE_EL1t: + exc_offset = CURRENT_EL_SP_EL0_VECTOR; + break; + case PSR_MODE_EL1h: + exc_offset = CURRENT_EL_SP_ELx_VECTOR; + break; + case PSR_MODE_EL0t: + exc_offset = LOWER_EL_AArch64_VECTOR; + break; + default: + exc_offset = LOWER_EL_AArch32_VECTOR; + } + + return vcpu_sys_reg(vcpu, VBAR_EL1) + exc_offset + type; +} + static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr) { unsigned long cpsr = *vcpu_cpsr(vcpu); @@ -108,8 +140,8 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr *vcpu_spsr(vcpu) = cpsr; *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu); + *vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync); *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64; - *vcpu_pc(vcpu) = vcpu_sys_reg(vcpu, VBAR_EL1) + EL1_EXCEPT_SYNC_OFFSET; vcpu_sys_reg(vcpu, FAR_EL1) = addr; @@ -143,8 +175,8 @@ static void inject_undef64(struct kvm_vcpu *vcpu) *vcpu_spsr(vcpu) = cpsr; *vcpu_elr_el1(vcpu) = *vcpu_pc(vcpu); + *vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync); *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64; - *vcpu_pc(vcpu) = vcpu_sys_reg(vcpu, VBAR_EL1) + EL1_EXCEPT_SYNC_OFFSET; /* * Build an unknown exception, depending on the instruction -- cgit v1.2.3 From a7e0ac295d964086af3bf98352614f33c381213e Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Tue, 19 Jan 2016 16:20:18 +0000 Subject: arm64: KVM: Obey RES0/1 reserved bits when setting CPTR_EL2 Some bits in CPTR are defined as RES1 in the architecture. Setting these bits to zero may unintentionally enable future architecture extensions, allowing guests to use them without supervision by the host. This would be bad: for forwards compatibility, this patch makes sure the affected bits are always written with 1, not 0. This patch only addresses CPTR_EL2. Initialisation of other system registers may still need review. Reviewed-by: Marc Zyngier Signed-off-by: Dave Martin Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_arm.h | 1 + arch/arm64/kvm/hyp/switch.c | 8 ++++++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 738a95f93e49..bef6e9243c63 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -182,6 +182,7 @@ #define CPTR_EL2_TCPAC (1 << 31) #define CPTR_EL2_TTA (1 << 20) #define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT) +#define CPTR_EL2_DEFAULT 0x000033ff /* Hyp Debug Configuration Register bits */ #define MDCR_EL2_TDRA (1 << 11) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index ca8f5a5e2f96..f0e7bdfae134 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -36,7 +36,11 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) write_sysreg(val, hcr_el2); /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */ write_sysreg(1 << 15, hstr_el2); - write_sysreg(CPTR_EL2_TTA | CPTR_EL2_TFP, cptr_el2); + + val = CPTR_EL2_DEFAULT; + val |= CPTR_EL2_TTA | CPTR_EL2_TFP; + write_sysreg(val, cptr_el2); + write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); } @@ -45,7 +49,7 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) write_sysreg(HCR_RW, hcr_el2); write_sysreg(0, hstr_el2); write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2); - write_sysreg(0, cptr_el2); + write_sysreg(CPTR_EL2_DEFAULT, cptr_el2); } static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From 9586a2ea6806599c819a9e800581c2a698ef7467 Mon Sep 17 00:00:00 2001 From: Shannon Zhao Date: Wed, 13 Jan 2016 17:16:39 +0800 Subject: arm64: KVM: Fix wrong use of the CPSR MODE mask for 32bit guests The values of CPSR MODE mask are different between aarch32 and aarch64. It should use the right one according to the execution state. Reviewed-by: Marc Zyngier Signed-off-by: Shannon Zhao Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_emulate.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 3066328cd86b..779a5872a2c5 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -127,10 +127,14 @@ static inline unsigned long *vcpu_spsr(const struct kvm_vcpu *vcpu) static inline bool vcpu_mode_priv(const struct kvm_vcpu *vcpu) { - u32 mode = *vcpu_cpsr(vcpu) & PSR_MODE_MASK; + u32 mode; - if (vcpu_mode_is_32bit(vcpu)) + if (vcpu_mode_is_32bit(vcpu)) { + mode = *vcpu_cpsr(vcpu) & COMPAT_PSR_MODE_MASK; return mode > COMPAT_PSR_MODE_USR; + } + + mode = *vcpu_cpsr(vcpu) & PSR_MODE_MASK; return mode != PSR_MODE_EL0t; } -- cgit v1.2.3 From 7769db905bd2df08e844b645437f4729fc1c4d20 Mon Sep 17 00:00:00 2001 From: Shannon Zhao Date: Wed, 13 Jan 2016 17:16:40 +0800 Subject: arm64: KVM: Fix comments of the CP handler Make sure the documentation reflects the actual name of the functions. Acked-by: Marc Zyngier Signed-off-by: Shannon Zhao Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index eec3598b4184..4048934bb3a5 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1043,7 +1043,7 @@ static void unhandled_cp_access(struct kvm_vcpu *vcpu, } /** - * kvm_handle_cp_64 -- handles a mrrc/mcrr trap on a guest CP15 access + * kvm_handle_cp_64 -- handles a mrrc/mcrr trap on a guest CP14/CP15 access * @vcpu: The VCPU pointer * @run: The kvm_run struct */ @@ -1095,7 +1095,7 @@ out: } /** - * kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15 access + * kvm_handle_cp_32 -- handles a mrc/mcr trap on a guest CP14/CP15 access * @vcpu: The VCPU pointer * @run: The kvm_run struct */ -- cgit v1.2.3 From 6327f35a2010c06a3bc2bfb14202a38764fb9920 Mon Sep 17 00:00:00 2001 From: Shannon Zhao Date: Wed, 13 Jan 2016 17:16:41 +0800 Subject: arm64: KVM: Fix guest dead loop when register accessor returns false Currently emulate_cp will return 0 (Handled) no matter what the accessor returns. If register accessor returns false, it will not skip current PC while emulate_cp return handled. Then guest will stuck in a dead loop. Reviewed-by: Marc Zyngier Signed-off-by: Shannon Zhao Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4048934bb3a5..2e90371cfb37 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1007,10 +1007,9 @@ static int emulate_cp(struct kvm_vcpu *vcpu, if (likely(r->access(vcpu, params, r))) { /* Skip instruction, since it was emulated */ kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + /* Handled */ + return 0; } - - /* Handled */ - return 0; } /* Not handled */ -- cgit v1.2.3