kernel/task: Remove p_vaddr alignment requirement from exec_user()

Elf spec doesn't require `p_vaddr` to be page aligned, so remove this
requirment and handle unaligned virtual start address in exec_user().

Signed-off-by: Vijay Dhanraj <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>

kernel/src/task/exec.rs

@@ -11,6 +11,7 @@ use crate::mm::vm::VMFileMappingFlags;
 use crate::mm::USER_MEM_END;
 use crate::task::{create_user_task, current_task, schedule};
 use crate::types::PAGE_SIZE;
+use crate::utils::align_up;
 use elf::{Elf64File, Elf64PhdrFlags};
 
 fn convert_elf_phdr_flags(flags: Elf64PhdrFlags) -> VMFileMappingFlags {
@@ -53,14 +54,26 @@ pub fn exec_user(binary: &str) -> Result<(), SvsmError> {
         let virt_end = VirtAddr::from(seg.vaddr_range.vaddr_end).align_up(PAGE_SIZE);
         let file_offset = seg.file_range.offset_begin;
         let len = virt_end - virt_start;
+        let file_size = seg.file_range.offset_end - seg.file_range.offset_begin;
         let flags = convert_elf_phdr_flags(seg.flags);
 
-        if !virt_start.is_aligned(PAGE_SIZE) {
-            return Err(SvsmError::Mem);
-        }
-
         if file_offset > 0 {
-            task.mmap_user(virt_start, Some(&fh), file_offset, len, flags)?;
+            if file_size > len {
+                return Err(SvsmError::Elf(elf::ElfError::InvalidFileRange));
+            }
+
+            // Handle unaligned VirtAddr and Offset
+            let start_aligned = virt_start.page_align();
+            let offset = file_offset - virt_start.page_offset();
+            let size = file_size + virt_start.page_offset();
+            task.mmap_user(start_aligned, Some(&fh), offset, size, flags)?;
+
+            let size_aligned = align_up(size, PAGE_SIZE);
+            if size_aligned < len {
+                let start_anon = start_aligned.const_add(size_aligned);
+                let remaining_len = len - size_aligned;
+                task.mmap_user(start_anon, None, 0, remaining_len, flags)?;
+            }
         } else {
             task.mmap_user(virt_start, None, 0, len, flags)?;
         }