HypMap clean-up

libuser/src/start.S

@@ -17,8 +17,8 @@ _start:
     la sp, _stack_end
 
     // a0 contains cpu id
-    // a1 contains the U-mode mapped area address
-    // a2 contains the U-mode mapped area size
+    // a1 contains the U-mode input region address
+    // a2 contains the U-mode input region size
     call task_main
 
     // ecall to panic

src/hyp_layout.rs

@@ -0,0 +1,87 @@
+// SPDX-FileCopyrightText: 2023 Rivos Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+// VM-Layout of Salus.
+//
+//
+// +-------------------------+ 0x0000_0000_0000_0000
+// | 1:1 HwMemoryMap         |
+// +-------------------------+ (Highest HwMemoryMap address)
+// | (unused)                |
+// +-------------------------+ 0xffff_ffff_0000_0000 (UMODE_START, UMODE_BINARY_START)
+// | U-mode ELF mappings     |
+// +-------------------------+ +UMODE_BINARY_SIZE (UMODE_BINARY_END)
+// | (unused 4Mb)            |
+// +-------------------------+ UMODE_MAPPINGS_START
+// | U-mode Slot A           |
+// +-------------------------+ +UMODE_MAPPINGS_SLOT_SIZE
+// | U-mode Slot B           |
+// +-------------------------+ +UMODE_MAPPINGS_SLOT_SIZE (UMODE_MAPPINGS_END)
+// | (unused 4Mb)            |
+// +-------------------------+ UMODE_INPUT_START
+// | Umode Input Area        |
+// +-------------------------+ +UMODE_INPUT_SIZE
+
+use riscv_pages::{PageAddr, PageSize, SupervisorVirt};
+use static_assertions::const_assert;
+
+/// U-mode mappings start here.
+pub const UMODE_START: u64 = 0xffff_ffff_0000_0000;
+/// U-mode binary mappings start here.
+pub const UMODE_BINARY_START: u64 = UMODE_START;
+/// Size in bytes of the U-mode binary VA area.
+pub const UMODE_BINARY_SIZE: u64 = 128 * 1024 * 1024;
+/// U-mode binary mappings end here.
+pub const UMODE_BINARY_END: u64 = UMODE_BINARY_START + UMODE_BINARY_SIZE;
+
+/// The addresses between `UMODE_MAPPINGS_START` and `UMODE_MAPPINGS_START` + `UMODE_MAPPINGS_SIZE`
+/// is an area of the private page table where the hypervisor can map pages shared from guest
+/// VMs. The area is divided in slots, of equal size `UMODE_MAPPING_SLOT_SIZE`.
+/// Must be multiple of 4k.
+pub const UMODE_MAPPING_SLOT_SIZE: u64 = 4 * 1024 * 1024;
+const_assert!(PageSize::Size4k.is_aligned(UMODE_MAPPING_SLOT_SIZE));
+
+/// Start of the private U-mode mappings area.  Must be 4k-aligned.
+pub const UMODE_MAPPINGS_START: u64 = UMODE_BINARY_END + 4 * 1024 * 1024;
+const_assert!(PageSize::Size4k.is_aligned(UMODE_MAPPINGS_START));
+/// The number of slots available for mapping.
+pub const UMODE_MAPPING_SLOTS: u64 = 2;
+
+/// Generic Id names for each of the U-mode mapping slots.
+/// There is no mandated use for each of the slots, and caller can decide to map each of them
+/// readable or writable based on the requirement.
+#[derive(Copy, Clone)]
+pub enum UmodeSlotId {
+    A,
+    B,
+}
+
+/// Maximum size of the private mappings area. Must be 4k-aligned.
+pub const UMODE_MAPPINGS_SIZE: u64 = UMODE_MAPPING_SLOTS * UMODE_MAPPING_SLOT_SIZE;
+/// Starting page address of slot A.
+pub const UMODE_MAPPINGS_A_PAGE_ADDR: PageAddr<SupervisorVirt> =
+    PageAddr::<SupervisorVirt>::new_const::<UMODE_MAPPINGS_START>();
+/// Starting page address of slot B.
+pub const UMODE_MAPPINGS_B_PAGE_ADDR: PageAddr<SupervisorVirt> =
+    PageAddr::<SupervisorVirt>::new_const::<{ UMODE_MAPPINGS_START + UMODE_MAPPING_SLOT_SIZE }>();
+/// End of the private U-mode mappings area. Must be 4k-aligned.
+pub const UMODE_MAPPINGS_END: u64 = UMODE_MAPPINGS_START + UMODE_MAPPINGS_SIZE;
+const_assert!(PageSize::Size4k.is_aligned(UMODE_MAPPINGS_END));
+
+/// Start of the U-mode Input Region.
+pub const UMODE_INPUT_START: u64 = UMODE_MAPPINGS_END + 4 * 1024 * 1024;
+const_assert!(PageSize::Size4k.is_aligned(UMODE_INPUT_START));
+/// Size of the U-mode Input Region.
+pub const UMODE_INPUT_SIZE: u64 = 4 * 1024;
+const_assert!(PageSize::Size4k.is_aligned(UMODE_INPUT_SIZE));
+
+// Returns true if `addr` is contained in the U-mode binary area.
+fn is_umode_binary_addr(addr: u64) -> bool {
+    (UMODE_BINARY_START..UMODE_BINARY_END).contains(&addr)
+}
+
+/// Returns true if (`addr`, `addr` + `len`) is a valid non-empty range in the VA area.
+pub fn is_valid_umode_binary_range(addr: u64, len: usize) -> bool {
+    len != 0 && is_umode_binary_addr(addr) && is_umode_binary_addr(addr + len as u64 - 1)
+}