Set values on other platforms

Signed-off-by: James Sturtevant <[email protected]>

Author: jsturtevant

src/hyperlight_host/src/hypervisor/gdb/hyperv_debug.rs

@@ -238,7 +238,7 @@ impl GuestDebug for HypervDebug {
 
     fn write_regs(&self, vcpu_fd: &Self::Vcpu, regs: &X86_64Regs) -> Result<()> {
         log::debug!("Write registers");
-        let regs = WHvGeneralRegisters {
+        let gprs = WHvGeneralRegisters {
             rax: regs.rax,
             rbx: regs.rbx,
             rcx: regs.rcx,
@@ -261,7 +261,37 @@ impl GuestDebug for HypervDebug {
         };
 
         vcpu_fd
-            .set_general_purpose_registers(&regs)
+            .set_general_purpose_registers(&gprs)
+            .map_err(|e| new_error!("Could not write guest registers: {:?}", e))?;
+
+        // Load existing FPU state, replace XMM and MXCSR, and write it back.
+        let mut fpu = match vcpu_fd.get_fpu() {
+            Ok(f) => f,
+            Err(e) => {
+                return Err(new_error!("Could not write guest registers: {:?}", e));
+            }
+        };
+
+        fpu.xmm0 = regs.xmm[0];
+        fpu.xmm1 = regs.xmm[1];
+        fpu.xmm2 = regs.xmm[2];
+        fpu.xmm3 = regs.xmm[3];
+        fpu.xmm4 = regs.xmm[4];
+        fpu.xmm5 = regs.xmm[5];
+        fpu.xmm6 = regs.xmm[6];
+        fpu.xmm7 = regs.xmm[7];
+        fpu.xmm8 = regs.xmm[8];
+        fpu.xmm9 = regs.xmm[9];
+        fpu.xmm10 = regs.xmm[10];
+        fpu.xmm11 = regs.xmm[11];
+        fpu.xmm12 = regs.xmm[12];
+        fpu.xmm13 = regs.xmm[13];
+        fpu.xmm14 = regs.xmm[14];
+        fpu.xmm15 = regs.xmm[15];
+        fpu.mxcsr = regs.mxcsr;
+
+        vcpu_fd
+            .set_fpu(&fpu)
             .map_err(|e| new_error!("Could not write guest registers: {:?}", e))
     }
 }

src/hyperlight_host/src/hypervisor/gdb/kvm_debug.rs

@@ -207,6 +207,7 @@ impl GuestDebug for KvmDebug {
         }
 
         // Read MXCSR from XSAVE (MXCSR is at byte offset 24 -> u32 index 6)
+        // 11.5.10 Mode-Specific XSAVE/XRSTOR State Management
         match vcpu_fd.get_xsave() {
             Ok(xsave) => {
                 regs.mxcsr = xsave.region[6];

src/hyperlight_host/src/hypervisor/gdb/mshv_debug.rs

@@ -274,6 +274,21 @@ impl GuestDebug for MshvDebug {
 
         vcpu_fd
             .set_regs(&new_regs)
+            .map_err(|e| new_error!("Could not write guest registers: {:?}", e))?;
+
+        // Load existing FPU state, replace XMM and MXCSR, and write it back.
+        let mut fpu = match vcpu_fd.get_fpu() {
+            Ok(f) => f,
+            Err(e) => {
+                return Err(new_error!("Could not write guest registers: {:?}", e));
+            }
+        };
+
+        fpu.xmm = regs.xmm.map(u128::to_le_bytes);
+        fpu.mxcsr = regs.mxcsr;
+
+        vcpu_fd
+            .set_fpu(&fpu)
             .map_err(|e| new_error!("Could not write guest registers: {:?}", e))
     }
 }