Re: [PATCH v4] arm64: kvm: inject SError with user space specified syndrome

From: gengdongjiu
Date: Mon Jul 03 2017 - 10:09:52 EST

Hi Christoffer,
thank you very much for your review.


2017-07-03 15:50 GMT+08:00, Christoffer Dall <cdall@xxxxxxxxxx>:
> Hi Dongjiu,
>
> It seems you sent this patch twice, once on its own and then part of a
> series?
Christoffer, yes, it is. once on its own and then part of a
series

>
> Also, please use a cover letter when sending patch series.
Ok, got it, thank you a lot for your suggestion.

>
> Thanks,
> -Christoffer
>
> On Mon, Jun 26, 2017 at 07:39:15PM +0800, Dongjiu Geng wrote:
>> when SError happen, kvm notifies user space to record the CPER,
>> user space specifies and passes the contents of ESR_EL1 on taking
>> a virtual SError interrupt to KVM, KVM enables virtual system
>> error or asynchronous abort with this specifies syndrome. This
>> patch modify the world-switch to restore VSESR_EL2, VSESR_EL2
>> saves the virtual SError syndrome, it becomes the ESR_EL1 value when
>> HCR_EL2.VSE injects an SError. This register is added by the
>> RAS Extensions.
>>
>> Changes since v3:
>> (1) Move restore VSESR_EL2 value logic to a helper method
>> (2) In the world-switch, not save VSESR_EL2, because no one cares the
>> old VSESR_EL2 value
>> (3) Add a new KVM_ARM_SEI ioctl to set the VSESR_EL2 value and pend
>> a virtual system error
>>
>> Signed-off-by: Dongjiu Geng <gengdongjiu@xxxxxxxxxx>
>> Signed-off-by: Quanming Wu <wuquanming@xxxxxxxxxx>
>> ---
>> Documentation/virtual/kvm/api.txt | 10 ++++++++++
>> arch/arm/include/asm/kvm_host.h | 1 +
>> arch/arm/kvm/arm.c | 6 ++++++
>> arch/arm/kvm/guest.c | 5 +++++
>> arch/arm64/include/asm/esr.h | 2 ++
>> arch/arm64/include/asm/kvm_emulate.h | 10 ++++++++++
>> arch/arm64/include/asm/kvm_host.h | 2 ++
>> arch/arm64/include/asm/sysreg.h | 3 +++
>> arch/arm64/kvm/guest.c | 14 ++++++++++++++
>> arch/arm64/kvm/handle_exit.c | 25 +++++++++++++++++++------
>> arch/arm64/kvm/hyp/switch.c | 14 ++++++++++++++
>> include/uapi/linux/kvm.h | 8 ++++++++
>> 12 files changed, 94 insertions(+), 6 deletions(-)
>>
>> diff --git a/Documentation/virtual/kvm/api.txt
>> b/Documentation/virtual/kvm/api.txt
>> index 3c248f7..852ac55 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -3377,6 +3377,16 @@ struct kvm_ppc_resize_hpt {
>> __u32 pad;
>> };
>>
>> +4.104 KVM_ARM_SEI
>> +
>> +Capability: KVM_EXIT_SERROR_INTR
>> +Architectures: arm/arm64
>> +Type: vcpu ioctl
>> +Parameters: u64 (syndrome)
>> +Returns: 0 in case of success
>> +
>> +Pend an virtual system error or asynchronous abort with user space
>> specified.
>> +
>> 5. The kvm_run structure
>> ------------------------
>>
>> diff --git a/arch/arm/include/asm/kvm_host.h
>> b/arch/arm/include/asm/kvm_host.h
>> index 31ee468..566292a 100644
>> --- a/arch/arm/include/asm/kvm_host.h
>> +++ b/arch/arm/include/asm/kvm_host.h
>> @@ -244,6 +244,7 @@ int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu,
>> const struct kvm_one_reg *);
>>
>> int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
>> int exception_index);
>> +int kvm_vcpu_ioctl_sei(struct kvm_vcpu *vcpu, u64 *syndrome);
>>
>> static inline void __cpu_init_hyp_mode(phys_addr_t pgd_ptr,
>> unsigned long hyp_stack_ptr,
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index 96dba7c..2622501 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -987,6 +987,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>> return -EFAULT;
>> return kvm_arm_vcpu_has_attr(vcpu, &attr);
>> }
>> + case KVM_ARM_SEI: {
>> + u64 syndrome;
>> + if (copy_from_user(&syndrome, argp, sizeof(syndrome)))
>> + return -EFAULT;
>> + return kvm_vcpu_ioctl_sei(vcpu, &syndrome);
>> + }
>> default:
>> return -EINVAL;
>> }
>> diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
>> index fa6182a..a610f8f 100644
>> --- a/arch/arm/kvm/guest.c
>> +++ b/arch/arm/kvm/guest.c
>> @@ -248,6 +248,11 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu
>> *vcpu,
>> return -EINVAL;
>> }
>>
>> +int kvm_vcpu_ioctl_sei(struct kvm_vcpu *vcpu, u64 *syndrome);
>> +{
>> + return 0;
>> +}
>> +
>> int __attribute_const__ kvm_target_cpu(void)
>> {
>> switch (read_cpuid_part()) {
>> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
>> index 22f9c90..d009c99 100644
>> --- a/arch/arm64/include/asm/esr.h
>> +++ b/arch/arm64/include/asm/esr.h
>> @@ -127,6 +127,8 @@
>> #define ESR_ELx_WFx_ISS_WFE (UL(1) << 0)
>> #define ESR_ELx_xVC_IMM_MASK ((1UL << 16) - 1)
>>
>> +#define VSESR_ELx_IDS_ISS_MASK ((1UL << 25) - 1)
>> +
>> /* ESR value templates for specific events */
>>
>> /* BRK instruction trap from AArch64 state */
>> diff --git a/arch/arm64/include/asm/kvm_emulate.h
>> b/arch/arm64/include/asm/kvm_emulate.h
>> index f5ea0ba..a3259a9 100644
>> --- a/arch/arm64/include/asm/kvm_emulate.h
>> +++ b/arch/arm64/include/asm/kvm_emulate.h
>> @@ -148,6 +148,16 @@ static inline u32 kvm_vcpu_get_hsr(const struct
>> kvm_vcpu *vcpu)
>> return vcpu->arch.fault.esr_el2;
>> }
>>
>> +static inline u32 kvm_vcpu_get_vsesr(const struct kvm_vcpu *vcpu)
>> +{
>> + return vcpu->arch.fault.vsesr_el2;
>> +}
>> +
>> +static inline void kvm_vcpu_set_vsesr(struct kvm_vcpu *vcpu, unsigned
>> long val)
>> +{
>> + vcpu->arch.fault.vsesr_el2 = val;
>> +}
>> +
>> static inline int kvm_vcpu_get_condition(const struct kvm_vcpu *vcpu)
>> {
>> u32 esr = kvm_vcpu_get_hsr(vcpu);
>> diff --git a/arch/arm64/include/asm/kvm_host.h
>> b/arch/arm64/include/asm/kvm_host.h
>> index e7705e7..b6242fb 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -86,6 +86,7 @@ struct kvm_vcpu_fault_info {
>> u32 esr_el2; /* Hyp Syndrom Register */
>> u64 far_el2; /* Hyp Fault Address Register */
>> u64 hpfar_el2; /* Hyp IPA Fault Address Register */
>> + u32 vsesr_el2; /* Virtual SError Exception Syndrome Register */
>> };
>>
>> /*
>> @@ -385,6 +386,7 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
>> struct kvm_device_attr *attr);
>> int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
>> struct kvm_device_attr *attr);
>> +int kvm_vcpu_ioctl_sei(struct kvm_vcpu *vcpu, u64 *syndrome);
>>
>> static inline void __cpu_init_stage2(void)
>> {
>> diff --git a/arch/arm64/include/asm/sysreg.h
>> b/arch/arm64/include/asm/sysreg.h
>> index 32964c7..3af6907 100644
>> --- a/arch/arm64/include/asm/sysreg.h
>> +++ b/arch/arm64/include/asm/sysreg.h
>> @@ -125,6 +125,9 @@
>> #define REG_PSTATE_PAN_IMM sys_reg(0, 0, 4, 0, 4)
>> #define REG_PSTATE_UAO_IMM sys_reg(0, 0, 4, 0, 3)
>>
>> +/* virtual SError exception syndrome register in armv8.2 */
>> +#define REG_VSESR_EL2 sys_reg(3, 4, 5, 2, 3)
>> +
>> #define SET_PSTATE_PAN(x) __emit_inst(0xd5000000 | REG_PSTATE_PAN_IMM
>> | \
>> (!!x)<<8 | 0x1f)
>> #define SET_PSTATE_UAO(x) __emit_inst(0xd5000000 | REG_PSTATE_UAO_IMM
>> | \
>> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
>> index b37446a..21c20b0 100644
>> --- a/arch/arm64/kvm/guest.c
>> +++ b/arch/arm64/kvm/guest.c
>> @@ -277,6 +277,20 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu
>> *vcpu,
>> return -EINVAL;
>> }
>>
>> +int kvm_vcpu_ioctl_sei(struct kvm_vcpu *vcpu, u64 *syndrome)
>> +{
>> + u64 reg = *syndrome;
>> +
>> + if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && reg)
>> + /* set vsesr_el2[24:0] with value that user space specified */
>> + kvm_vcpu_set_vsesr(vcpu, reg & VSESR_ELx_IDS_ISS_MASK);
>> +
>> + /* inject virtual system Error or asynchronous abort */
>> + kvm_inject_vabt(vcpu);
>> +
>> + return 0;
>> +}
>> +
>> int __attribute_const__ kvm_target_cpu(void)
>> {
>> unsigned long implementor = read_cpuid_implementor();
>> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
>> index c89d83a..23c02c2 100644
>> --- a/arch/arm64/kvm/handle_exit.c
>> +++ b/arch/arm64/kvm/handle_exit.c
>> @@ -180,7 +180,11 @@ static exit_handle_fn kvm_get_exit_handler(struct
>> kvm_vcpu *vcpu)
>>
>> static int kvm_handle_guest_sei(struct kvm_vcpu *vcpu, struct kvm_run
>> *run)
>> {
>> - unsigned long fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
>> + unsigned long hva, fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
>> + struct kvm_memory_slot *memslot;
>> + int hsr, ret = 1;
>> + bool writable;
>> + gfn_t gfn;
>>
>> if (handle_guest_sei((unsigned long)fault_ipa,
>> kvm_vcpu_get_hsr(vcpu))) {
>> @@ -190,9 +194,20 @@ static int kvm_handle_guest_sei(struct kvm_vcpu
>> *vcpu, struct kvm_run *run)
>> (unsigned long)kvm_vcpu_get_hsr(vcpu));
>>
>> kvm_inject_vabt(vcpu);
>> + } else {
>> + hsr = kvm_vcpu_get_hsr(vcpu);
>> +
>> + gfn = fault_ipa >> PAGE_SHIFT;
>> + memslot = gfn_to_memslot(vcpu->kvm, gfn);
>> + hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
>> +
>> + run->exit_reason = KVM_EXIT_SERROR_INTR;
>> + run->serror_intr.syndrome_info = hsr;
>> + run->serror_intr.address = hva;
>> + ret = 0;
>> }
>>
>> - return 0;
>> + return ret;
>> }
>>
>> /*
>> @@ -218,8 +233,7 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run
>> *run,
>> *vcpu_pc(vcpu) -= adj;
>> }
>>
>> - kvm_handle_guest_sei(vcpu, run);
>> - return 1;
>> + return kvm_handle_guest_sei(vcpu, run);
>> }
>>
>> exception_index = ARM_EXCEPTION_CODE(exception_index);
>> @@ -228,8 +242,7 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run
>> *run,
>> case ARM_EXCEPTION_IRQ:
>> return 1;
>> case ARM_EXCEPTION_EL1_SERROR:
>> - kvm_handle_guest_sei(vcpu, run);
>> - return 1;
>> + return kvm_handle_guest_sei(vcpu, run);
>> case ARM_EXCEPTION_TRAP:
>> /*
>> * See ARM ARM B1.14.1: "Hyp traps on instructions
>> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
>> index aede165..6d17c97 100644
>> --- a/arch/arm64/kvm/hyp/switch.c
>> +++ b/arch/arm64/kvm/hyp/switch.c
>> @@ -67,6 +67,13 @@ static hyp_alternate_select(__activate_traps_arch,
>> __activate_traps_nvhe, __activate_traps_vhe,
>> ARM64_HAS_VIRT_HOST_EXTN);
>>
>> +static void __hyp_text __sysreg_set_vsesr(struct kvm_vcpu *vcpu)
>> +{
>> + if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) &&
>> + (vcpu->arch.hcr_el2 & HCR_VSE))
>> + write_sysreg_s(vcpu->arch.fault.vsesr_el2, REG_VSESR_EL2);
>> +}
>> +
>> static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
>> {
>> u64 val;
>> @@ -86,6 +93,13 @@ static void __hyp_text __activate_traps(struct kvm_vcpu
>> *vcpu)
>> isb();
>> }
>> write_sysreg(val, hcr_el2);
>> +
>> + /*
>> + * If the virtual SError interrupt is taken to EL1 using AArch64,
>> + * then VSESR_EL2 provides the syndrome value reported in ESR_EL1.
>> + */
>> + __sysreg_set_vsesr(vcpu);
>> +
>> /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
>> write_sysreg(1 << 15, hstr_el2);
>> /*
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index 27fe556..ab91fe3 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -205,6 +205,7 @@ struct kvm_hyperv_exit {
>> #define KVM_EXIT_S390_STSI 25
>> #define KVM_EXIT_IOAPIC_EOI 26
>> #define KVM_EXIT_HYPERV 27
>> +#define KVM_EXIT_SERROR_INTR 28
>>
>> /* For KVM_EXIT_INTERNAL_ERROR */
>> /* Emulate instruction failed. */
>> @@ -360,6 +361,11 @@ struct kvm_run {
>> struct {
>> __u8 vector;
>> } eoi;
>> + /* KVM_EXIT_SERROR_INTR */
>> + struct {
>> + __u32 syndrome_info;
>> + __u64 address;
>> + } serror_intr;
>> /* KVM_EXIT_HYPERV */
>> struct kvm_hyperv_exit hyperv;
>> /* Fix the size of the union. */
>> @@ -1301,6 +1307,8 @@ struct kvm_s390_ucas_mapping {
>> #define KVM_S390_GET_IRQ_STATE _IOW(KVMIO, 0xb6, struct
>> kvm_s390_irq_state)
>> /* Available with KVM_CAP_X86_SMM */
>> #define KVM_SMI _IO(KVMIO, 0xb7)
>> +/* Available with KVM_EXIT_SERROR_INTR */
>> +#define KVM_ARM_SEI _IO(KVMIO, 0xb8)
>>
>> #define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
>> #define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
>> --
>> 2.10.1
>>
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