KVM: x86: Push potential exception error code on task switches

When a fault triggers a task switch, the error code, if existent, has to
be pushed on the new task's stack. Implement the missing bits.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index a1319c8..0b2729b 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -230,6 +230,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt,
                     struct x86_emulate_ops *ops);
 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
                         struct x86_emulate_ops *ops,
                     struct x86_emulate_ops *ops);
 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
                         struct x86_emulate_ops *ops,

-                        u16 tss_selector, int reason);
+                        u16 tss_selector, int reason,
+                        bool has_error_code, u32 error_code);

 
 #endif /* _ASM_X86_KVM_X86_EMULATE_H */
 
 #endif /* _ASM_X86_KVM_X86_EMULATE_H */

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5d5e0a9..3602728 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -595,7 +595,8 @@ int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
 void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
 int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
 
 void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
 int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
 

-int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason);
+int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
+                   bool has_error_code, u32 error_code);

 
 void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
 void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
 
 void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
 void kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 1d91d05..0e83105 100644 (file)
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -244,6 +244,7 @@ struct __attribute__ ((__packed__)) vmcb {
 
 #define SVM_EXITINFOSHIFT_TS_REASON_IRET 36
 #define SVM_EXITINFOSHIFT_TS_REASON_JMP 38
 
 #define SVM_EXITINFOSHIFT_TS_REASON_IRET 36
 #define SVM_EXITINFOSHIFT_TS_REASON_JMP 38

+#define SVM_EXITINFOSHIFT_TS_HAS_ERROR_CODE 44

 
 #define        SVM_EXIT_READ_CR0       0x000
 #define        SVM_EXIT_READ_CR3       0x003
 
 #define        SVM_EXIT_READ_CR0       0x000
 #define        SVM_EXIT_READ_CR3       0x003

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index aace565..585d0ef 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2344,8 +2344,9 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
 }
 
 static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
 }
 
 static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,

-                                   struct x86_emulate_ops *ops,
-                                   u16 tss_selector, int reason)
+                                  struct x86_emulate_ops *ops,
+                                  u16 tss_selector, int reason,
+                                  bool has_error_code, u32 error_code)

 {
        struct desc_struct curr_tss_desc, next_tss_desc;
        int ret;
 {
        struct desc_struct curr_tss_desc, next_tss_desc;
        int ret;


@@ -2418,12 +2419,22 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
        ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu);
        ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu);
 
        ops->set_cached_descriptor(&next_tss_desc, VCPU_SREG_TR, ctxt->vcpu);
        ops->set_segment_selector(tss_selector, VCPU_SREG_TR, ctxt->vcpu);
 

+       if (has_error_code) {
+               struct decode_cache *c = &ctxt->decode;
+
+               c->op_bytes = c->ad_bytes = (next_tss_desc.type & 8) ? 4 : 2;
+               c->lock_prefix = 0;
+               c->src.val = (unsigned long) error_code;
+               emulate_push(ctxt);
+       }
+

        return ret;
 }
 
 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
                         struct x86_emulate_ops *ops,
        return ret;
 }
 
 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
                         struct x86_emulate_ops *ops,

-                        u16 tss_selector, int reason)
+                        u16 tss_selector, int reason,
+                        bool has_error_code, u32 error_code)

 {
        struct decode_cache *c = &ctxt->decode;
        int rc;
 {
        struct decode_cache *c = &ctxt->decode;
        int rc;


@@ -2431,12 +2442,15 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
        memset(c, 0, sizeof(struct decode_cache));
        c->eip = ctxt->eip;
        memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);
        memset(c, 0, sizeof(struct decode_cache));
        c->eip = ctxt->eip;
        memcpy(c->regs, ctxt->vcpu->arch.regs, sizeof c->regs);

+       c->dst.type = OP_NONE;

 
 

-       rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason);
+       rc = emulator_do_task_switch(ctxt, ops, tss_selector, reason,
+                                    has_error_code, error_code);

 
        if (rc == X86EMUL_CONTINUE) {
                memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
                kvm_rip_write(ctxt->vcpu, c->eip);
 
        if (rc == X86EMUL_CONTINUE) {
                memcpy(ctxt->vcpu->arch.regs, c->regs, sizeof c->regs);
                kvm_rip_write(ctxt->vcpu, c->eip);

+               rc = writeback(ctxt, ops);

        }
 
        return rc;
        }
 
        return rc;

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 87b36fb..78af522 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2222,6 +2222,8 @@ static int task_switch_interception(struct vcpu_svm *svm)
                svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_TYPE_MASK;
        uint32_t idt_v =
                svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_VALID;
                svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_TYPE_MASK;
        uint32_t idt_v =
                svm->vmcb->control.exit_int_info & SVM_EXITINTINFO_VALID;

+       bool has_error_code = false;
+       u32 error_code = 0;

 
        tss_selector = (u16)svm->vmcb->control.exit_info_1;
 
 
        tss_selector = (u16)svm->vmcb->control.exit_info_1;
 


@@ -2242,6 +2244,12 @@ static int task_switch_interception(struct vcpu_svm *svm)
                        svm->vcpu.arch.nmi_injected = false;
                        break;
                case SVM_EXITINTINFO_TYPE_EXEPT:
                        svm->vcpu.arch.nmi_injected = false;
                        break;
                case SVM_EXITINTINFO_TYPE_EXEPT:

+                       if (svm->vmcb->control.exit_info_2 &
+                           (1ULL << SVM_EXITINFOSHIFT_TS_HAS_ERROR_CODE)) {
+                               has_error_code = true;
+                               error_code =
+                                       (u32)svm->vmcb->control.exit_info_2;
+                       }

                        kvm_clear_exception_queue(&svm->vcpu);
                        break;
                case SVM_EXITINTINFO_TYPE_INTR:
                        kvm_clear_exception_queue(&svm->vcpu);
                        break;
                case SVM_EXITINTINFO_TYPE_INTR:


@@ -2258,7 +2266,8 @@ static int task_switch_interception(struct vcpu_svm *svm)
             (int_vec == OF_VECTOR || int_vec == BP_VECTOR)))
                skip_emulated_instruction(&svm->vcpu);
 
             (int_vec == OF_VECTOR || int_vec == BP_VECTOR)))
                skip_emulated_instruction(&svm->vcpu);
 

-       return kvm_task_switch(&svm->vcpu, tss_selector, reason);
+       return kvm_task_switch(&svm->vcpu, tss_selector, reason,
+                              has_error_code, error_code);

 }
 
 static int cpuid_interception(struct vcpu_svm *svm)
 }
 
 static int cpuid_interception(struct vcpu_svm *svm)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index fb4a886..1b38d8a 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3271,6 +3271,8 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
        unsigned long exit_qualification;
 {
        struct vcpu_vmx *vmx = to_vmx(vcpu);
        unsigned long exit_qualification;

+       bool has_error_code = false;
+       u32 error_code = 0;

        u16 tss_selector;
        int reason, type, idt_v;
 
        u16 tss_selector;
        int reason, type, idt_v;
 


@@ -3293,6 +3295,13 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
                        kvm_clear_interrupt_queue(vcpu);
                        break;
                case INTR_TYPE_HARD_EXCEPTION:
                        kvm_clear_interrupt_queue(vcpu);
                        break;
                case INTR_TYPE_HARD_EXCEPTION:

+                       if (vmx->idt_vectoring_info &
+                           VECTORING_INFO_DELIVER_CODE_MASK) {
+                               has_error_code = true;
+                               error_code =
+                                       vmcs_read32(IDT_VECTORING_ERROR_CODE);
+                       }
+                       /* fall through */

                case INTR_TYPE_SOFT_EXCEPTION:
                        kvm_clear_exception_queue(vcpu);
                        break;
                case INTR_TYPE_SOFT_EXCEPTION:
                        kvm_clear_exception_queue(vcpu);
                        break;


@@ -3307,7 +3316,8 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
                       type != INTR_TYPE_NMI_INTR))
                skip_emulated_instruction(vcpu);
 
                       type != INTR_TYPE_NMI_INTR))
                skip_emulated_instruction(vcpu);
 

-       if (!kvm_task_switch(vcpu, tss_selector, reason))
+       if (!kvm_task_switch(vcpu, tss_selector, reason, has_error_code,
+                            error_code))

                return 0;
 
        /* clear all local breakpoint enable flags */
                return 0;
 
        /* clear all local breakpoint enable flags */

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4099152..58a295c 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4778,7 +4778,8 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
        return 0;
 }
 
        return 0;
 }
 

-int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
+int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
+                   bool has_error_code, u32 error_code)

 {
        int cs_db, cs_l, ret;
        cache_all_regs(vcpu);
 {
        int cs_db, cs_l, ret;
        cache_all_regs(vcpu);


@@ -4796,7 +4797,8 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason)
                ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
 
        ret = emulator_task_switch(&vcpu->arch.emulate_ctxt, &emulate_ops,
                ? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
 
        ret = emulator_task_switch(&vcpu->arch.emulate_ctxt, &emulate_ops,

-                                  tss_selector, reason);
+                                  tss_selector, reason, has_error_code,
+                                  error_code);

 
        if (ret == X86EMUL_CONTINUE)
                kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);
 
        if (ret == X86EMUL_CONTINUE)
                kvm_x86_ops->set_rflags(vcpu, vcpu->arch.emulate_ctxt.eflags);