Merge #618

618: Fix SMP with 3 or more CPUs r=mkroening a=mkroening

Closes https://github.com/hermitcore/libhermit-rs/issues/617

.

Co-authored-by: Martin Kröning <mkroening@posteo.net>

.gitlab-ci.yml

@@ -94,10 +94,10 @@ test:qemu:
         -display none -m 64M -serial stdio -enable-kvm
         -kernel /usr/local/bin/rusty-loader-x86_64
         -initrd rusty-hermit/target/x86_64-unknown-hermit/debug/rusty_demo
-     - qemu-system-x86_64 -smp 2
+     - qemu-system-x86_64 -smp 4
         -cpu qemu64,apic,fsgsbase,rdtscp,xsave,xsaveopt,fxsr,rdrand
         -device isa-debug-exit,iobase=0xf4,iosize=0x04
-        -display none -m 64M -serial stdio -enable-kvm
+        -display none -m 128M -serial stdio -enable-kvm
         -kernel /usr/local/bin/rusty-loader-x86_64
         -initrd rusty-hermit/target/x86_64-unknown-hermit/debug/rusty_demo
      - qemu-system-x86_64 -smp 1
@@ -106,10 +106,10 @@ test:qemu:
         -display none -m 64M -serial stdio -enable-kvm
         -kernel /usr/local/bin/rusty-loader-x86_64
         -initrd rusty-hermit/target/x86_64-unknown-hermit/release/rusty_demo
-     - qemu-system-x86_64 -smp 2
+     - qemu-system-x86_64 -smp 4
         -cpu qemu64,apic,fsgsbase,rdtscp,xsave,xsaveopt,fxsr,rdrand
         -device isa-debug-exit,iobase=0xf4,iosize=0x04
-        -display none -m 64M -serial stdio -enable-kvm
+        -display none -m 128M -serial stdio -enable-kvm
         -kernel /usr/local/bin/rusty-loader-x86_64
         -initrd rusty-hermit/target/x86_64-unknown-hermit/release/rusty_demo
    tags:

src/arch/x86_64/kernel/gdt.rs

@@ -21,7 +21,7 @@ pub const GDT_KERNEL_DATA: u16 = 2;
 pub const GDT_FIRST_TSS: u16 = 3;
 
 /// We dynamically allocate a GDT large enough to hold the maximum number of entries.
-const GDT_ENTRIES: usize = 8;
+const GDT_ENTRIES: usize = 8192;
 
 static mut GDT: Gdt = Gdt::new();
 

src/arch/x86_64/mm/paging.rs

@@ -111,10 +111,17 @@ pub fn map<S>(
 
 	trace!("Mapping {pages:?} to {frames:?} with {flags:?}");
 
+	#[cfg(feature = "smp")]
+	let mut ipi_tlb_flush = false;
+
 	for (page, frame) in pages.zip(frames) {
 		unsafe {
 			// TODO: Require explicit unmaps
 			if let Ok((_frame, flush)) = recursive_page_table().unmap(page) {
+				#[cfg(feature = "smp")]
+				{
+					ipi_tlb_flush = true;
+				}
 				flush.flush();
 			}
 			recursive_page_table()
@@ -125,7 +132,9 @@ pub fn map<S>(
 	}
 
 	#[cfg(feature = "smp")]
-	crate::arch::x86_64::kernel::apic::ipi_tlb_flush();
+	if ipi_tlb_flush {
+		crate::arch::x86_64::kernel::apic::ipi_tlb_flush();
+	}
 }
 
 pub fn map_heap<S: PageSize>(virt_addr: VirtAddr, count: usize)