1. AMD SVM
syuu1228 from @livedoor

2. SVM
AMD
Intel-VT
VMM
qemu
↑

3. SVM
Ring Host/Guest
Guest
DMA Host/Guest
Guest
Guest
Tagged TLB
Nested Paging

4. Host
Guest
VMM
ex:

5. Guest
VMCB VMRUN Guest
VMCB Guest
Host ex:
Host
AMD #VMEXIT
Host #VMEXIT VMRUN

6. Host Guest
Guest VMRUN
λ... #VMEXIT
Host #VMEXIT VMRUN

7. VMCB
Virtual Machine Control Block
VM VMCB
4KB aligned 4KB 1
Control area
Guest CPU Save state area

8. Control Area (1)
on/off bit
R/W
,
I/O
MSR

9. Control Area (2)
I/O Permissons Map
IO
MSR Permissons Map
MSR
Time stamp counter
RDTSC, RDTSCP

10. Control Area (3)
TLB , Guest ASID(TLB tag )
#VMEXIT
Nested Paging
Event Injection
Guest
LBR
LBR Last Branch Record)AMD64

11. Save state area
RIP,RSP,RAX
ES,CS,SS,DS,FS,GS
STAR,LSTAR,CSTAR
GDTR,LDTR,IDTR
SFMASK
TR
KernelGsBase
CPL
SYSENTER_CS,SYSENTER
CR0,CR2,CR3,CR4
_ESP,SYSENTER_EIP
DR6,DR7
PAT
RFLAGS
LBR registers
RBX

12. …
Save state area
Guest
(RBX,RCX,RDX,RSI,RDI,RBI)
Host (!!!!)

13. …
Guest
"mov %c[rbx](%[svm]), %%ebx nt" ※kvm-6
"mov %c[rcx](%[svm]), %%ecx nt"
"mov %c[rdx](%[svm]), %%edx nt"
"mov %c[rsi](%[svm]), %%esi nt"
"mov %c[rdi](%[svm]), %%edi nt"
"mov %c[rbp](%[svm]), %%ebp nt"
/* Enter guest mode */
"push %%eax nt"
"mov %c[vmcb](%[svm]), %%eax nt"
SVM_VMLOAD "nt"
SVM_VMRUN "nt"
SVM_VMSAVE "nt"
"pop %%eax nt"
/* Save guest registers, load host registers */
"mov %%ebx, %c[rbx](%[svm]) nt"
"mov %%ecx, %c[rcx](%[svm]) nt"
"mov %%edx, %c[rdx](%[svm]) nt"
"mov %%esi, %c[rsi](%[svm]) nt"
"mov %%edi, %c[rdi](%[svm]) nt"
"mov %%ebp, %c[rbp](%[svm]) nt"
mov ;)

14. Host
__asm __volatile ( ※kvm-6
"push %%ebx; push %%ecx; push %%edx;"
"push %%esi; push %%edi; push %%ebp;"
"pop %%ebp; pop %%edi; pop %%esi;"
"pop %%edx; pop %%ecx; pop %%ebx; nt"
push/pop

15. Host
MSR,FS,GS,LDT,CR2,DR0-3,DR6-7,TR

16. SVM
VM_HSAVE_PA on MSR
SVM MSR
Host
VMRUN/#VMEXIT
CS,SS,RIP,RSP,CR0,CR4,EFER,IDTR,GDTR

17. /* Enter guest mode */ ※kvm-6
"push %%eax nt"
"mov %c[vmcb](%[svm]), %%eax nt"
SVM_VMLOAD "nt"
SVM_VMRUN "nt"
SVM_VMSAVE "nt"
"pop %%eax nt"
VMRUN

18. VMLOAD/VMSAVE
VMRUN/#VMEXIT
CS,RIP,RFLAGS,RAX,SS,RSP,CR0,CR2-4,EFER,IDTR,GDTR,ES,DS,DR6-7,CPL
→VMLOAD/VMSAVE
FS,GS,TR,LDTR,KernelGsBase,STAR,LSTAR,CSTAR,SFMASK,SYSENTER_CS,SY
SENTER_ESP,SYSENTER_EIP
KVM VMLOAD→VMRUN→VMSAVE

19. Host
Host
Guest
Guest VMLOAD)
Host (VMRUN)
Guest (VMRUN)
Guest !!!
Guest (#VMEXIT)
Host (#VMEXIT)
Guest (VMSAVE)
Guest
Host
Host