[PATCH 3/3] KVM: x86: simplify RSM into 64-bit protected mode

From: Radim KrÄmÃÅ
Date: Fri Oct 30 2015 - 11:37:31 EST


This reverts 0123456789abc ("KVM: x86: fix RSM into 64-bit protected
mode, round 2"). We've achieved the same by treating SMBASE as a
physical address in the previous patch.

Signed-off-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 37 +++++++------------------------------
1 file changed, 7 insertions(+), 30 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 59e80e0de865..b60fed56671b 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2311,16 +2311,7 @@ static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
return X86EMUL_CONTINUE;
}

-struct rsm_stashed_seg_64 {
- u16 selector;
- struct desc_struct desc;
- u32 base3;
-};
-
-static int rsm_stash_seg_64(struct x86_emulate_ctxt *ctxt,
- struct rsm_stashed_seg_64 *stash,
- u64 smbase,
- int n)
+static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
{
struct desc_struct desc;
int offset;
@@ -2335,20 +2326,10 @@ static int rsm_stash_seg_64(struct x86_emulate_ctxt *ctxt,
set_desc_base(&desc, GET_SMSTATE(u32, smbase, offset + 8));
base3 = GET_SMSTATE(u32, smbase, offset + 12);

- stash[n].selector = selector;
- stash[n].desc = desc;
- stash[n].base3 = base3;
+ ctxt->ops->set_segment(ctxt, selector, &desc, base3, n);
return X86EMUL_CONTINUE;
}

-static inline void rsm_load_seg_64(struct x86_emulate_ctxt *ctxt,
- struct rsm_stashed_seg_64 *stash,
- int n)
-{
- ctxt->ops->set_segment(ctxt, stash[n].selector, &stash[n].desc,
- stash[n].base3, n);
-}
-
static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
u64 cr0, u64 cr4)
{
@@ -2438,7 +2419,6 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
u32 base3;
u16 selector;
int i, r;
- struct rsm_stashed_seg_64 stash[6];

for (i = 0; i < 16; i++)
*reg_write(ctxt, i) = GET_SMSTATE(u64, smbase, 0x7ff8 - i * 8);
@@ -2480,18 +2460,15 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
dt.address = GET_SMSTATE(u64, smbase, 0x7e68);
ctxt->ops->set_gdt(ctxt, &dt);

- for (i = 0; i < ARRAY_SIZE(stash); i++) {
- r = rsm_stash_seg_64(ctxt, stash, smbase, i);
- if (r != X86EMUL_CONTINUE)
- return r;
- }
-
r = rsm_enter_protected_mode(ctxt, cr0, cr4);
if (r != X86EMUL_CONTINUE)
return r;

- for (i = 0; i < ARRAY_SIZE(stash); i++)
- rsm_load_seg_64(ctxt, stash, i);
+ for (i = 0; i < 6; i++) {
+ r = rsm_load_seg_64(ctxt, smbase, i);
+ if (r != X86EMUL_CONTINUE)
+ return r;
+ }

return X86EMUL_CONTINUE;
}
--
2.5.3

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