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[v2,1/9] i386: hvf: Set env->eip in macvm_set_rip()

Message ID 20200630102824.77604-2-r.bolshakov@yadro.com
State New
Headers show
Series Improve synchronization between QEMU and HVF | expand

Commit Message

Roman Bolshakov June 30, 2020, 10:28 a.m. UTC 
cpu_synchronize_state() is currently no-op for hvf but BIOS will hang in
vAPIC option ROM when cpu_synchronize_state() is wired to
hvf_cpu_synchronize_state().

cpu_synchronize_state() state is called from vapic_write() during option
ROM initialization. It sets dirty flag on the cpu. macvm_set_rip() is
then invoked to advance IP after the I/O write to vAPIC port.

macvm_set_rip() only modifies VMCS, it doesn't change env->eip.
Therefore on the next iteration of vCPU loop, vcpu_dirty flag is checked
and hvf_put_registers() overwrites correct RIP in VMCS with the value of
env->eip that points to the I/O write instruction. Execution of the CPU
gets stuck on the instruction.

The issue can be avoided if eip doesn't contain stale value when dirty
flag is set on cpu.

Cc: Cameron Esfahani <dirty@apple.com>
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
---
 target/i386/hvf/vmx.h | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/target/i386/hvf/vmx.h b/target/i386/hvf/vmx.h
index ce2a1532d5..1e8b29bf7d 100644
--- a/target/i386/hvf/vmx.h
+++ b/target/i386/hvf/vmx.h
@@ -173,6 +173,7 @@  static inline void macvm_set_rip(CPUState *cpu, uint64_t rip)
 
     /* BUG, should take considering overlap.. */
     wreg(cpu->hvf_fd, HV_X86_RIP, rip);
+    env->eip = rip;
 
     /* after moving forward in rip, we need to clean INTERRUPTABILITY */
    val = rvmcs(cpu->hvf_fd, VMCS_GUEST_INTERRUPTIBILITY);