[guest/entrypoint,host/drivers] change the ABI of entrypoint from win64

Originally, because we only supported PE, our entrypoint used the win64 ABI. Now, with PE file support being
removed, we can use an ABI that wouldn't be restrictive in compiling the guest library to targets that don't
support the win64 ABI.

Signed-off-by: danbugs <[email protected]>

Author: danbugs

src/hyperlight_guest/src/entrypoint.rs

@@ -76,7 +76,7 @@ static INIT: Once = Once::new();
 // Note: entrypoint cannot currently have a stackframe >4KB, as that will invoke __chkstk on msvc
 //       target without first having setup global `RUNNING_MODE` variable, which __chkstk relies on.
 #[no_mangle]
-pub extern "win64" fn entrypoint(peb_address: u64, seed: u64, ops: u64, max_log_level: u64) {
+pub extern "C" fn entrypoint(peb_address: u64, seed: u64, ops: u64, max_log_level: u64) {
     if peb_address == 0 {
         panic!("PEB address is null");
     }

src/hyperlight_host/src/hypervisor/hyperv_linux.rs

@@ -476,10 +476,10 @@ impl Hypervisor for HypervLinuxDriver {
             rflags: 2, //bit 1 of rlags is required to be set
 
             // function args
-            rcx: peb_addr.into(),
-            rdx: seed,
-            r8: page_size.into(),
-            r9: max_guest_log_level,
+            rdi: peb_addr.into(),
+            rsi: seed,
+            rdx: page_size.into(),
+            rcx: max_guest_log_level,
 
             ..Default::default()
         };

src/hyperlight_host/src/hypervisor/hyperv_windows.rs

@@ -321,10 +321,10 @@ impl Hypervisor for HypervWindowsDriver {
             rsp: self.orig_rsp.absolute()?,
 
             // function args
-            rcx: peb_address.into(),
-            rdx: seed,
-            r8: page_size.into(),
-            r9: max_guest_log_level,
+            rdi: peb_address.into(),
+            rsi: seed,
+            rdx: page_size.into(),
+            rcx: max_guest_log_level,
             rflags: 1 << 1, // eflags bit index 1 is reserved and always needs to be 1
 
             ..Default::default()

src/hyperlight_host/src/hypervisor/kvm.rs

@@ -420,10 +420,10 @@ impl Hypervisor for KVMDriver {
             rsp: self.orig_rsp.absolute()?,
 
             // function args
-            rcx: peb_addr.into(),
-            rdx: seed,
-            r8: page_size.into(),
-            r9: max_guest_log_level,
+            rdi: peb_addr.into(),
+            rsi: seed,
+            rdx: page_size.into(),
+            rcx: max_guest_log_level,
 
             ..Default::default()
         };