[v8,12/19] hvf: Simplify post reset/init/loadvm hooks

Commit Message

Alexander Graf May 19, 2021, 8:22 p.m. UTC

The hooks we have that call us after reset, init and loadvm really all
just want to say "The reference of all register state is in the QEMU
vcpu struct, please push it".

We already have a working pushing mechanism though called cpu->vcpu_dirty,
so we can just reuse that for all of the above, syncing state properly the
next time we actually execute a vCPU.

This fixes PSCI resets on ARM, as they modify CPU state even after the
post init call has completed, but before we execute the vCPU again.

To also make the scheme work for x86, we have to make sure we don't
move stale eflags into our env when the vcpu state is dirty.

Signed-off-by: Alexander Graf <[e-mail]>
Reviewed-by: Roman Bolshakov <[e-mail]>
Tested-by: Roman Bolshakov <[e-mail]>
---
 accel/hvf/hvf-accel-ops.c | 27 +++++++--------------------
 target/i386/hvf/x86hvf.c  |  5 ++++-
 2 files changed, 11 insertions(+), 21 deletions(-)

Comments

Sergio Lopez May 27, 2021, 10:20 a.m. UTC | #1

On Wed, May 19, 2021 at 10:22:46PM +0200, Alexander Graf wrote:
> The hooks we have that call us after reset, init and loadvm really all
> just want to say "The reference of all register state is in the QEMU
> vcpu struct, please push it".
> 
> We already have a working pushing mechanism though called cpu->vcpu_dirty,
> so we can just reuse that for all of the above, syncing state properly the
> next time we actually execute a vCPU.
> 
> This fixes PSCI resets on ARM, as they modify CPU state even after the
> post init call has completed, but before we execute the vCPU again.
> 
> To also make the scheme work for x86, we have to make sure we don't
> move stale eflags into our env when the vcpu state is dirty.
> 
> Signed-off-by: Alexander Graf <[e-mail]>
> Reviewed-by: Roman Bolshakov <[e-mail]>
> Tested-by: Roman Bolshakov <[e-mail]>
> ---
>  accel/hvf/hvf-accel-ops.c | 27 +++++++--------------------
>  target/i386/hvf/x86hvf.c  |  5 ++++-
>  2 files changed, 11 insertions(+), 21 deletions(-)

Reviewed-by: Sergio Lopez <[e-mail]>

Patch

diff --git a/accel/hvf/hvf-accel-ops.c b/accel/hvf/hvf-accel-ops.c
index ded918c443..d1691be989 100644
--- a/accel/hvf/hvf-accel-ops.c
+++ b/accel/hvf/hvf-accel-ops.c
@@ -205,39 +205,26 @@  static void hvf_cpu_synchronize_state(CPUState *cpu)
     }
 }
 
-static void do_hvf_cpu_synchronize_post_reset(CPUState *cpu,
-                                              run_on_cpu_data arg)
+static void do_hvf_cpu_synchronize_set_dirty(CPUState *cpu,
+                                             run_on_cpu_data arg)
 {
-    hvf_put_registers(cpu);
-    cpu->vcpu_dirty = false;
+    /* QEMU state is the reference, push it to HVF now and on next entry */
+    cpu->vcpu_dirty = true;
 }
 
 static void hvf_cpu_synchronize_post_reset(CPUState *cpu)
 {
-    run_on_cpu(cpu, do_hvf_cpu_synchronize_post_reset, RUN_ON_CPU_NULL);
-}
-
-static void do_hvf_cpu_synchronize_post_init(CPUState *cpu,
-                                             run_on_cpu_data arg)
-{
-    hvf_put_registers(cpu);
-    cpu->vcpu_dirty = false;
+    run_on_cpu(cpu, do_hvf_cpu_synchronize_set_dirty, RUN_ON_CPU_NULL);
 }
 
 static void hvf_cpu_synchronize_post_init(CPUState *cpu)
 {
-    run_on_cpu(cpu, do_hvf_cpu_synchronize_post_init, RUN_ON_CPU_NULL);
-}
-
-static void do_hvf_cpu_synchronize_pre_loadvm(CPUState *cpu,
-                                              run_on_cpu_data arg)
-{
-    cpu->vcpu_dirty = true;
+    run_on_cpu(cpu, do_hvf_cpu_synchronize_set_dirty, RUN_ON_CPU_NULL);
 }
 
 static void hvf_cpu_synchronize_pre_loadvm(CPUState *cpu)
 {
-    run_on_cpu(cpu, do_hvf_cpu_synchronize_pre_loadvm, RUN_ON_CPU_NULL);
+    run_on_cpu(cpu, do_hvf_cpu_synchronize_set_dirty, RUN_ON_CPU_NULL);
 }
 
 static void hvf_set_dirty_tracking(MemoryRegionSection *section, bool on)
diff --git a/target/i386/hvf/x86hvf.c b/target/i386/hvf/x86hvf.c
index 28cfee4f60..2ced2c2478 100644
--- a/target/i386/hvf/x86hvf.c
+++ b/target/i386/hvf/x86hvf.c
@@ -433,7 +433,10 @@  int hvf_process_events(CPUState *cpu_state)
     X86CPU *cpu = X86_CPU(cpu_state);
     CPUX86State *env = &cpu->env;
 
-    env->eflags = rreg(cpu_state->hvf->fd, HV_X86_RFLAGS);
+    if (!cpu_state->vcpu_dirty) {
+        /* light weight sync for CPU_INTERRUPT_HARD and IF_MASK */
+        env->eflags = rreg(cpu_state->hvf->fd, HV_X86_RFLAGS);
+    }
 
     if (cpu_state->interrupt_request & CPU_INTERRUPT_INIT) {
         cpu_synchronize_state(cpu_state);