patch rdrand availability check for debuggingnd enable KVM

Author: Juliette Pretot

experimental/uefi/app/.cargo/config.toml

@@ -7,7 +7,7 @@ runner = "qemu-system-x86_64 -nodefaults -nographic -bios /usr/share/OVMF/OVMF_C
 
 # Otherwise, (a) the first serial port gets routed to a log, and (b) the second serial gets attached to stdio.
 [target.'cfg(not(test))']
-runner = "qemu-system-x86_64 -nodefaults -nographic -bios /usr/share/OVMF/OVMF_CODE.fd -serial file:target/console.log -serial stdio -machine q35 -device isa-debug-exit,iobase=0xf4,iosize=0x04 -kernel"
+runner = "qemu-system-x86_64 -enable-kvm -cpu Broadwell-IBRS,vme=on,f16c=on,rdrand=on -nodefaults -nographic -bios /usr/share/OVMF/OVMF_CODE.fd -serial file:target/console.log -serial stdio -machine q35 -device isa-debug-exit,iobase=0xf4,iosize=0x04 -kernel"
 
 [unstable]
 build-std = ["core", "alloc"]

third_party/ring/src/rand.rs

@@ -452,7 +452,11 @@ mod uefi {
                 static mut OPENSSL_ia32cap_P: [u32; 4];
             }
             const FLAG: u32 = 1 << 30;
-            unsafe { OPENSSL_ia32cap_P[1] & FLAG == FLAG }
+            // Somehow this check continues to require patching, regardless
+            // of qemu CPU config. :/. That is even though RDRAND is in fact
+            // available and working.
+            // unsafe { OPENSSL_ia32cap_P[1] & FLAG == FLAG }
+            true
         }
 
         // We must make sure current cpu support `rdrand`