KVM: x86: Virtualize debug registers

[sfrench/cifs-2.6.git] / arch / x86 / kvm / svm.c

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 88d9062f454501bb5e4750e87f635bbc4a660a70..815f50e425ac31a0181bc54f8086d3ba5d893fe2 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -38,9 +38,6 @@ MODULE_LICENSE("GPL");
 #define IOPM_ALLOC_ORDER 2
 #define MSRPM_ALLOC_ORDER 1
 
-#define DR7_GD_MASK (1 << 13)
-#define DR6_BD_MASK (1 << 13)
-
 #define SEG_TYPE_LDT 2
 #define SEG_TYPE_BUSY_TSS16 3
 
@@ -181,32 +178,6 @@ static inline void kvm_write_cr2(unsigned long val)
        asm volatile ("mov %0, %%cr2" :: "r" (val));
 }
 
-static inline unsigned long read_dr6(void)
-{
-       unsigned long dr6;
-
-       asm volatile ("mov %%dr6, %0" : "=r" (dr6));
-       return dr6;
-}
-
-static inline void write_dr6(unsigned long val)
-{
-       asm volatile ("mov %0, %%dr6" :: "r" (val));
-}
-
-static inline unsigned long read_dr7(void)
-{
-       unsigned long dr7;
-
-       asm volatile ("mov %%dr7, %0" : "=r" (dr7));
-       return dr7;
-}
-
-static inline void write_dr7(unsigned long val)
-{
-       asm volatile ("mov %0, %%dr7" :: "r" (val));
-}
-
 static inline void force_new_asid(struct kvm_vcpu *vcpu)
 {
        to_svm(vcpu)->asid_generation--;
@@ -695,7 +666,6 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
        clear_page(svm->vmcb);
        svm->vmcb_pa = page_to_pfn(page) << PAGE_SHIFT;
        svm->asid_generation = 0;
-       memset(svm->db_regs, 0, sizeof(svm->db_regs));
        init_vmcb(svm);
 
        fx_init(&svm->vcpu);
@@ -1035,7 +1005,29 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *svm_data)
 
 static unsigned long svm_get_dr(struct kvm_vcpu *vcpu, int dr)
 {
-       unsigned long val = to_svm(vcpu)->db_regs[dr];
+       struct vcpu_svm *svm = to_svm(vcpu);
+       unsigned long val;
+
+       switch (dr) {
+       case 0 ... 3:
+               val = vcpu->arch.db[dr];
+               break;
+       case 6:
+               if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+                       val = vcpu->arch.dr6;
+               else
+                       val = svm->vmcb->save.dr6;
+               break;
+       case 7:
+               if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+                       val = vcpu->arch.dr7;
+               else
+                       val = svm->vmcb->save.dr7;
+               break;
+       default:
+               val = 0;
+       }
+
        KVMTRACE_2D(DR_READ, vcpu, (u32)dr, (u32)val, handler);
        return val;
 }
@@ -1045,33 +1037,40 @@ static void svm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long value,
 {
        struct vcpu_svm *svm = to_svm(vcpu);
 
-       *exception = 0;
+       KVMTRACE_2D(DR_WRITE, vcpu, (u32)dr, (u32)value, handler);
 
-       if (svm->vmcb->save.dr7 & DR7_GD_MASK) {
-               svm->vmcb->save.dr7 &= ~DR7_GD_MASK;
-               svm->vmcb->save.dr6 |= DR6_BD_MASK;
-               *exception = DB_VECTOR;
-               return;
-       }
+       *exception = 0;
 
        switch (dr) {
        case 0 ... 3:
-               svm->db_regs[dr] = value;
+               vcpu->arch.db[dr] = value;
+               if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+                       vcpu->arch.eff_db[dr] = value;
                return;
        case 4 ... 5:
-               if (vcpu->arch.cr4 & X86_CR4_DE) {
+               if (vcpu->arch.cr4 & X86_CR4_DE)
                        *exception = UD_VECTOR;
+               return;
+       case 6:
+               if (value & 0xffffffff00000000ULL) {
+                       *exception = GP_VECTOR;
                        return;
                }
-       case 7: {
-               if (value & ~((1ULL << 32) - 1)) {
+               vcpu->arch.dr6 = (value & DR6_VOLATILE) | DR6_FIXED_1;
+               return;
+       case 7:
+               if (value & 0xffffffff00000000ULL) {
                        *exception = GP_VECTOR;
                        return;
                }
-               svm->vmcb->save.dr7 = value;
+               vcpu->arch.dr7 = (value & DR7_VOLATILE) | DR7_FIXED_1;
+               if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) {
+                       svm->vmcb->save.dr7 = vcpu->arch.dr7;
+                       vcpu->arch.switch_db_regs = (value & DR7_BP_EN_MASK);
+               }
                return;
-       }
        default:
+               /* FIXME: Possible case? */
                printk(KERN_DEBUG "%s: unexpected dr %u\n",
                       __func__, dr);
                *exception = UD_VECTOR;
@@ -2365,22 +2364,6 @@ static int svm_set_tss_addr(struct kvm *kvm, unsigned int addr)
        return 0;
 }
 
-static void save_db_regs(unsigned long *db_regs)
-{
-       asm volatile ("mov %%dr0, %0" : "=r"(db_regs[0]));
-       asm volatile ("mov %%dr1, %0" : "=r"(db_regs[1]));
-       asm volatile ("mov %%dr2, %0" : "=r"(db_regs[2]));
-       asm volatile ("mov %%dr3, %0" : "=r"(db_regs[3]));
-}
-
-static void load_db_regs(unsigned long *db_regs)
-{
-       asm volatile ("mov %0, %%dr0" : : "r"(db_regs[0]));
-       asm volatile ("mov %0, %%dr1" : : "r"(db_regs[1]));
-       asm volatile ("mov %0, %%dr2" : : "r"(db_regs[2]));
-       asm volatile ("mov %0, %%dr3" : : "r"(db_regs[3]));
-}
-
 static void svm_flush_tlb(struct kvm_vcpu *vcpu)
 {
        force_new_asid(vcpu);
@@ -2439,20 +2422,12 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
        gs_selector = kvm_read_gs();
        ldt_selector = kvm_read_ldt();
        svm->host_cr2 = kvm_read_cr2();
-       svm->host_dr6 = read_dr6();
-       svm->host_dr7 = read_dr7();
        if (!is_nested(svm))
                svm->vmcb->save.cr2 = vcpu->arch.cr2;
        /* required for live migration with NPT */
        if (npt_enabled)
                svm->vmcb->save.cr3 = vcpu->arch.cr3;
 
-       if (svm->vmcb->save.dr7 & 0xff) {
-               write_dr7(0);
-               save_db_regs(svm->host_db_regs);
-               load_db_regs(svm->db_regs);
-       }
-
        clgi();
 
        local_irq_enable();
@@ -2528,16 +2503,11 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 #endif
                );
 
-       if ((svm->vmcb->save.dr7 & 0xff))
-               load_db_regs(svm->host_db_regs);
-
        vcpu->arch.cr2 = svm->vmcb->save.cr2;
        vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
        vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
        vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
 
-       write_dr6(svm->host_dr6);
-       write_dr7(svm->host_dr7);
        kvm_write_cr2(svm->host_cr2);
 
        kvm_load_fs(fs_selector);