target/i386: emulate: add new callbacks

On Hyper-V fetching some guest registers is really expensive, so
add a way to query some state from information provided by Hyper-V
to save time on vmexits.

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
Link: https://lore.kernel.org/r/20260324151323.74473-7-mohamed@unpredictable.fr
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/emulate/x86_emu.h b/target/i386/emulate/x86_emu.h
index 0f284b0c3d150c66ce356570a856a8a2ef60500d..4ed970bd53664027a4a4ad9e2d6d373fdc8c56c9 100644 (file)
--- a/target/i386/emulate/x86_emu.h
+++ b/target/i386/emulate/x86_emu.h
@@ -32,6 +32,9 @@ struct x86_emul_ops {
                       int size, int count);
     void (*simulate_rdmsr)(CPUState *cs);
     void (*simulate_wrmsr)(CPUState *cs);
+    bool (*is_protected_mode)(CPUState *cpu);
+    bool (*is_long_mode)(CPUState *cpu);
+    bool (*is_user_mode)(CPUState *cpu);
 };
 
 extern const struct x86_emul_ops *emul_ops;

diff --git a/target/i386/emulate/x86_helpers.c b/target/i386/emulate/x86_helpers.c
index 024f9a2afcf102c4e29a68b95fb89743973fd51c..ebbf40f2b05b58a9cc0eeb5cd50fab28fa0463ed 100644 (file)
--- a/target/i386/emulate/x86_helpers.c
+++ b/target/i386/emulate/x86_helpers.c
@@ -211,6 +211,9 @@ bool x86_is_protected(CPUState *cpu)
     X86CPU *x86_cpu = X86_CPU(cpu);
     CPUX86State *env = &x86_cpu->env;
     uint64_t cr0 = env->cr[0];
+    if (emul_ops->is_protected_mode) {
+        return emul_ops->is_protected_mode(cpu);
+    }
 
     return cr0 & CR0_PE_MASK;
 }
@@ -234,6 +237,9 @@ bool x86_is_long_mode(CPUState *cpu)
     uint64_t efer = env->efer;
     uint64_t lme_lma = (MSR_EFER_LME | MSR_EFER_LMA);
 
+    if (emul_ops->is_long_mode) {
+        return emul_ops->is_long_mode(cpu);
+    }
     return ((efer & lme_lma) == lme_lma);
 }
 

diff --git a/target/i386/emulate/x86_mmu.c b/target/i386/emulate/x86_mmu.c
index 4e39bae025e7760e1d20fa9321dd18f070cbabae..670939acdbabffc998d2c3b59829c078514ec405 100644 (file)
--- a/target/i386/emulate/x86_mmu.c
+++ b/target/i386/emulate/x86_mmu.c
@@ -49,6 +49,9 @@
 
 static bool is_user(CPUState *cpu)
 {
+    if (emul_ops->is_user_mode) {
+        return emul_ops->is_user_mode(cpu);
+    }
     return false;
 }