From 2de451a329cf662beeba71f63c7f83ee24ca6642 Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Fri, 22 Sep 2023 12:25:07 +0100 Subject: KVM: arm64: Add handler for MOPS exceptions An Armv8.8 FEAT_MOPS main or epilogue instruction will take an exception if executed on a CPU with a different MOPS implementation option (A or B) than the CPU where the preceding prologue instruction ran. In this case the OS exception handler is expected to reset the registers and restart execution from the prologue instruction. A KVM guest may use the instructions at EL1 at times when the guest is not able to handle the exception, expecting that the instructions will only run on one CPU (e.g. when running UEFI boot services in the guest). As KVM may reschedule the guest between different types of CPUs at any time (on an asymmetric system), it needs to also handle the resulting exception itself in case the guest is not able to. A similar situation will also occur in the future when live migrating a guest from one type of CPU to another. Add handling for the MOPS exception to KVM. The handling can be shared with the EL0 exception handler, as the logic and register layouts are the same. The exception can be handled right after exiting a guest, which avoids the cost of returning to the host exit handler. Similarly to the EL0 exception handler, in case the main or epilogue instruction is being single stepped, it makes sense to finish the step before executing the prologue instruction, so advance the single step state machine. Signed-off-by: Kristina Martsenko Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20230922112508.1774352-2-kristina.martsenko@arm.com Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/include/hyp/switch.h | 17 +++++++++++++++++ arch/arm64/kvm/hyp/nvhe/switch.c | 2 ++ arch/arm64/kvm/hyp/vhe/switch.c | 1 + 3 files changed, 20 insertions(+) (limited to 'arch/arm64/kvm/hyp') diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 9cfe6bd1dbe4..f99d8af0b9af 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -30,6 +30,7 @@ #include #include #include +#include struct kvm_exception_table_entry { int insn, fixup; @@ -265,6 +266,22 @@ static inline bool __populate_fault_info(struct kvm_vcpu *vcpu) return __get_fault_info(vcpu->arch.fault.esr_el2, &vcpu->arch.fault); } +static bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code) +{ + *vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR); + arm64_mops_reset_regs(vcpu_gp_regs(vcpu), vcpu->arch.fault.esr_el2); + write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR); + + /* + * Finish potential single step before executing the prologue + * instruction. + */ + *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; + write_sysreg_el2(*vcpu_cpsr(vcpu), SYS_SPSR); + + return true; +} + static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu) { sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL2); diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index c353a06ee7e6..c50f8459e4fc 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -192,6 +192,7 @@ static const exit_handler_fn hyp_exit_handlers[] = { [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low, [ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low, [ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth, + [ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops, }; static const exit_handler_fn pvm_exit_handlers[] = { @@ -203,6 +204,7 @@ static const exit_handler_fn pvm_exit_handlers[] = { [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low, [ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low, [ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth, + [ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops, }; static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 6537f58b1a8c..796202f2e08f 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -126,6 +126,7 @@ static const exit_handler_fn hyp_exit_handlers[] = { [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low, [ESR_ELx_EC_WATCHPT_LOW] = kvm_hyp_handle_watchpt_low, [ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth, + [ESR_ELx_EC_MOPS] = kvm_hyp_handle_mops, }; static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu) -- cgit v1.2.3 From e0bb80c62cfd0c289c841d35e412e633299530e3 Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Fri, 22 Sep 2023 12:25:08 +0100 Subject: KVM: arm64: Expose MOPS instructions to guests Expose the Armv8.8 FEAT_MOPS feature to guests in the ID register and allow the MOPS instructions to be run in a guest. Only expose MOPS if the whole system supports it. Note, it is expected that guests do not use these instructions on MMIO, similarly to other instructions where ESR_EL2.ISV==0 such as LDP/STP. Signed-off-by: Kristina Martsenko Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20230922112508.1774352-3-kristina.martsenko@arm.com Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/include/nvhe/fixed_config.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/arm64/kvm/hyp') diff --git a/arch/arm64/kvm/hyp/include/nvhe/fixed_config.h b/arch/arm64/kvm/hyp/include/nvhe/fixed_config.h index 37440e1dda93..e91922daa8ca 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/fixed_config.h +++ b/arch/arm64/kvm/hyp/include/nvhe/fixed_config.h @@ -197,7 +197,8 @@ #define PVM_ID_AA64ISAR2_ALLOW (\ ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_GPA3) | \ - ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_APA3) \ + ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_APA3) | \ + ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_MOPS) \ ) u64 pvm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id); -- cgit v1.2.3