[PATCH 4.19 29/91] selftests: kvm: Fix the segment descriptor layout to match the actual layout

Greg Kroah-Hartman
2020-11-23T12:31:09Z

From: Aaron Lewis <aaronlewis@google.com>

[ Upstream commit df11f7dd5834146defa448acba097e8d7703cc42 ]

Fix the layout of 'struct desc64' to match the layout described in the
SDM Vol 3, Chapter 3 "Protected-Mode Memory Management", section 3.4.5
"Segment Descriptors", Figure 3-8 "Segment Descriptor". The test added
later in this series relies on this and crashes if this layout is not
correct.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Message-Id: <20201012194716.3950330-2-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/kvm/include/x86.h | 2 +-
tools/testing/selftests/kvm/lib/x86.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86.h b/tools/testing/selftests/kvm/include/x86.h
index 42c3596815b83..a7667a613bbc7 100644
--- a/tools/testing/selftests/kvm/include/x86.h
+++ b/tools/testing/selftests/kvm/include/x86.h
@@ -59,7 +59,7 @@ enum x86_register {
struct desc64 {
uint16_t limit0;
uint16_t base0;
- unsigned base1:8, s:1, type:4, dpl:2, p:1;
+ unsigned base1:8, type:4, s:1, dpl:2, p:1;
unsigned limit1:4, avl:1, l:1, db:1, g:1, base2:8;
uint32_t base3;
uint32_t zero1;
diff --git a/tools/testing/selftests/kvm/lib/x86.c b/tools/testing/selftests/kvm/lib/x86.c
index 4d35eba73dc97..800fe36064f9a 100644
--- a/tools/testing/selftests/kvm/lib/x86.c
+++ b/tools/testing/selftests/kvm/lib/x86.c
@@ -449,11 +449,12 @@ static void kvm_seg_fill_gdt_64bit(struct kvm_vm *vm, struct kvm_segment *segp)
desc->limit0 = segp->limit & 0xFFFF;
desc->base0 = segp->base & 0xFFFF;
desc->base1 = segp->base >> 16;
- desc->s = segp->s;
desc->type = segp->type;
+ desc->s = segp->s;
desc->dpl = segp->dpl;
desc->p = segp->present;
desc->limit1 = segp->limit >> 16;
+ desc->avl = segp->avl;
desc->l = segp->l;
desc->db = segp->db;
desc->g = segp->g;
--
2.27.0