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 a1319c82050e83bd2787b962dff241c4332bfec4..0b2729bf207055ce1621bd8a92872f5b9909694b 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,
-                        u16 tss_selector, int reason);
+                        u16 tss_selector, int reason,
+                        bool has_error_code, u32 error_code);
 
 #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 5d5e0a9afcf26d59117b899ca033397129b5201f..3602728d54de78a3595f5383ea6ebaa88343f885 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);
 
-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);

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index 1d91d05f93680db4b6cd2f57336f8d3827711d16..0e831059ac5ae83de16a740e087b105f376ae3cd 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_HAS_ERROR_CODE 44
 
 #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 aace5659bbe09dcbab20f7fcecba753c0ef4eff4..585d0ef4a5f6edea21409932f8f04da3aa9a1e14 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,
-                                   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;
@@ -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);
 
+       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,
-                        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;
@@ -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);
+       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);
+               rc = writeback(ctxt, ops);
        }
 
        return rc;

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 87b36fbbfec83474b5298a0fee92a5bf6c8934e8..78af52222fd2d9f58ecb2e42b061702100e2dbca 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;
+       bool has_error_code = false;
+       u32 error_code = 0;
 
        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:
+                       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:
@@ -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);
 
-       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)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index fb4a8869bb99760ab4e88656697ec7e17631036a..1b38d8a88cf70fc7360560f6ece12fb43238c75f 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;
+       bool has_error_code = false;
+       u32 error_code = 0;
        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:
+                       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;
@@ -3307,7 +3316,8 @@ static int handle_task_switch(struct kvm_vcpu *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 */

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 40991527f54afe13035b8e0c2c9311b41d323530..58a295c6bf62e85789ebeee1f379cd9680660c2f 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;
 }
 
-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);
@@ -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,
-                                  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);