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DO NOT MERGE: FreeBSD gdb modifications #231

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66 changes: 66 additions & 0 deletions ukvm/ukvm_gdb_freebsd_x86_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,71 @@
#include "ukvm_gdb_x86_64.h"
#include "ukvm_gdb.h"

#if 0
#define KVM_GUESTDBG_ENABLE 0x00000001
#define KVM_GUESTDBG_SINGLESTEP 0x00000002

static int ukvm_gdb_update_guest_debug(struct ukvm_hv *hv)
{
struct kvm_guest_debug dbg = {0};
struct breakpoint_t *bp;
const uint8_t type_code[] = {
/* Break on instruction execution only. */
[GDB_BREAKPOINT_HW] = 0x0,
/* Break on data writes only. */
[GDB_WATCHPOINT_WRITE] = 0x1,
/* Break on data reads only. */
[GDB_WATCHPOINT_READ] = 0x2,
/* Break on data reads or writes but not instruction fetches. */
[GDB_WATCHPOINT_ACCESS] = 0x3
};
const uint8_t len_code[] = {
/*
* 00 \xe2\x80\x94 1-byte length.
* 01 \xe2\x80\x94 2-byte length.
* 10 \xe2\x80\x94 8-byte length.
* 11 \xe2\x80\x94 4-byte length.
*/
[1] = 0x0, [2] = 0x1, [4] = 0x3, [8] = 0x2
};
int n = 0;

if (stepping)
dbg.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;

if (!SLIST_EMPTY(&sw_breakpoints))
dbg.control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;

if (!SLIST_EMPTY(&hw_breakpoints)) {
dbg.control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;

/* Enable global breakpointing (across all threads) on the control
* debug register. */
dbg.arch.debugreg[7] = 1 << 9;
dbg.arch.debugreg[7] |= 1 << 10;
SLIST_FOREACH(bp, &hw_breakpoints, entries) {
assert(bp->type != GDB_BREAKPOINT_SW);
dbg.arch.debugreg[n] = bp->addr;
/* global breakpointing */
dbg.arch.debugreg[7] |= (2 << (n * 2));
/* read/write fields */
dbg.arch.debugreg[7] |= (type_code[bp->type] << (16 + n*4));
/* Length fields */
dbg.arch.debugreg[7] |= ((uint32_t)len_code[bp->len] << (18 + n*4));
n++;
}
}

if (ioctl(hv->b->vcpufd, KVM_SET_GUEST_DEBUG, &dbg) == -1) {
/* The KVM_CAP_SET_GUEST_DEBUG capbility is not available. */
err(1, "KVM_SET_GUEST_DEBUG failed");
return -1;
}

return 0;
}
#endif

int ukvm_gdb_supported(void)
{
return -1;
Expand All @@ -58,6 +123,7 @@ int ukvm_gdb_write_registers(struct ukvm_hv *hv,

int ukvm_gdb_enable_ss(struct ukvm_hv *hv)
{
VM_REG_GUEST_DR7
return -1;
}

Expand Down
44 changes: 41 additions & 3 deletions ukvm/ukvm_hv_freebsd_x86_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,18 @@ static void vmm_set_desc(int vmfd, int reg, uint64_t base, uint32_t limit,
err(1, "VM_SET_SEGMENT_DESCRIPTOR (%d)", reg);
}

static void vmm_get_reg(int vmfd, int reg, uint64_t *val)
{
struct vm_register vmreg = {
.cpuid = 0, .regnum = reg
};

if (ioctl(vmfd, VM_SET_REGISTER, &vmreg) == -1)
err(1, "VM_SET_REGISTER (%d)", reg);

*val = vmreg.regval;
}

static void vmm_set_reg(int vmfd, int reg, uint64_t val)
{
struct vm_register vmreg = {
Expand Down Expand Up @@ -93,6 +105,10 @@ static void vmm_set_sreg(int vmfd, int reg, const struct x86_sreg *sreg)
vmm_set_reg(vmfd, reg, sreg->selector * 8);
}


#define KVM_GUESTDBG_ENABLE 0x00000001
#define KVM_GUESTDBG_SINGLESTEP 0x00000002

void ukvm_hv_vcpu_init(struct ukvm_hv *hv, ukvm_gpa_t gpa_ep,
ukvm_gpa_t gpa_kend, char **cmdline)
{
Expand All @@ -106,6 +122,8 @@ void ukvm_hv_vcpu_init(struct ukvm_hv *hv, ukvm_gpa_t gpa_ep,
vmm_set_reg(hvb->vmfd, VM_REG_GUEST_CR4, X86_CR4_INIT);
vmm_set_reg(hvb->vmfd, VM_REG_GUEST_EFER, X86_EFER_INIT);

//vmm_set_reg(hvb->vmfd, VM_REG_GUEST_DR7, KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP);

vmm_set_sreg(hvb->vmfd, VM_REG_GUEST_CS, &ukvm_x86_sreg_code);
vmm_set_sreg(hvb->vmfd, VM_REG_GUEST_SS, &ukvm_x86_sreg_data);
vmm_set_sreg(hvb->vmfd, VM_REG_GUEST_DS, &ukvm_x86_sreg_data);
Expand Down Expand Up @@ -152,7 +170,7 @@ void ukvm_hv_vcpu_init(struct ukvm_hv *hv, ukvm_gpa_t gpa_ep,
*cmdline = (char *)(hv->mem + X86_CMDLINE_BASE);
}

static void dump_vmx(struct vm_exit *vme)
void dump_vmx(struct vm_exit *vme)
{
warnx("unhandled VMX exit:");
warnx("\trip\t\t0x%016lx", vme->rip);
Expand All @@ -164,19 +182,32 @@ static void dump_vmx(struct vm_exit *vme)
warnx("\tinst_error\t%d", vme->u.vmx.inst_error);
}

void enable_eflag(struct ukvm_hv *hv, int flag)
{
struct ukvm_hvb *hvb = hv->b;
uint64_t flags;

vmm_get_reg(hvb->vmfd, VM_REG_GUEST_RFLAGS, &flags);
flags |= _BITUL(flag);
vmm_set_reg(hvb->vmfd, VM_REG_GUEST_RFLAGS, flags);
}

void ukvm_hv_vcpu_loop(struct ukvm_hv *hv)
{
struct ukvm_hvb *hvb = hv->b;
int ret;

while (1) {
enable_eflag(hv, 8); // ss

ret = ioctl(hv->b->vmfd, VM_RUN, &hvb->vmrun);
if (ret == -1 && errno == EINTR)
continue;
if (ret == -1) {
err(1, "VM_RUN");
}


int handled = 0;
for (ukvm_vmexit_fn_t *fn = ukvm_core_vmexits; *fn && !handled; fn++)
handled = ((*fn)(hv) == 0);
Expand All @@ -185,6 +216,9 @@ void ukvm_hv_vcpu_loop(struct ukvm_hv *hv)

struct vm_exit *vme = &hvb->vmrun.vm_exit;

vmm_set_reg(hvb->vmfd, VM_REG_GUEST_RIP, vme->rip + vme->inst_length);
enable_eflag(hv, 16); // resume

switch (vme->exitcode) {
case VM_EXITCODE_SUSPENDED:
/* Guest has halted the CPU, this is considered as a normal exit. */
Expand Down Expand Up @@ -220,8 +254,12 @@ void ukvm_hv_vcpu_loop(struct ukvm_hv *hv)
}

case VM_EXITCODE_VMX: {
dump_vmx(vme);
exit(1);
if (vme->u.vmx.status != 0) {
dump_vmx(vme);
exit(1);
}
printf("\trip\t\t0x%016lx\n", vme->rip);
break;
}

default: {
Expand Down