Re: [PATCH 2/2] x86/pvh: extract only 4 bytes of start address for 32 bit kernels

[Stefano Garzarella <sgarzare@redhat.com>]

On Tue, Mar 02, 2021 at 09:03:15AM +0000, David Edmondson wrote:
>When loading the PVH start address from a 32 bit ELF note, extract
>only the appropriate number of bytes.
>
>Fixes: ab969087da65 ("pvh: Boot uncompressed kernel using direct boot ABI")
>Signed-off-by: David Edmondson <david.edmondson@oracle.com>
>---
> hw/i386/x86.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/hw/i386/x86.c b/hw/i386/x86.c
>index 6329f90ef9..7865660e2c 100644
>--- a/hw/i386/x86.c
>+++ b/hw/i386/x86.c
>@@ -690,6 +690,8 @@ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, bool is64)
>         elf_note_data_addr =
>             ((void *)nhdr64) + nhdr_size64 +
>             QEMU_ALIGN_UP(nhdr_namesz, phdr_align);
>+
>+        pvh_start_addr = *elf_note_data_addr;
>     } else {
>         struct elf32_note *nhdr32 = (struct elf32_note *)arg1;
>         uint32_t nhdr_size32 = sizeof(struct elf32_note);
>@@ -699,9 +701,9 @@ static uint64_t read_pvh_start_addr(void *arg1, void *arg2, bool is64)
>         elf_note_data_addr =
>             ((void *)nhdr32) + nhdr_size32 +
>             QEMU_ALIGN_UP(nhdr_namesz, phdr_align);
>-    }
>
>-    pvh_start_addr = *elf_note_data_addr;
>+        pvh_start_addr = *(uint32_t *)elf_note_data_addr;
>+    }
>
>     return pvh_start_addr;
> }
>-- 
>2.30.0
>
>

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>