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kvm: x86: fix RSM when PCID is non-zero

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rsm_load_state_64() and rsm_enter_protected_mode() load CR3, then
CR4 & ~PCIDE, then CR0, then CR4.

However, setting CR4.PCIDE fails if CR3[11:0] != 0.  It's probably easier
in the long run to replace rsm_enter_protected_mode() with an emulator
callback that sets all the special registers (like KVM_SET_SREGS would
do).  For now, set the PCID field of CR3 only after CR4.PCIDE is 1.

Reported-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Fixes: 660a5d517a
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-12-21 00:49:14 +01:00
parent 43aabca38a
commit fae1a3e775
1 changed files with 25 additions and 7 deletions
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32
arch/x86/kvm/emulate.c
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@ -2390,9 +2390,21 @@ static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
}
static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
u64 cr0, u64 cr4)
u64 cr0, u64 cr3, u64 cr4)
{
int bad;
u64 pcid;
/* In order to later set CR4.PCIDE, CR3[11:0] must be zero. */
pcid = 0;
if (cr4 & X86_CR4_PCIDE) {
pcid = cr3 & 0xfff;
cr3 &= ~0xfff;
}
bad = ctxt->ops->set_cr(ctxt, 3, cr3);
if (bad)
return X86EMUL_UNHANDLEABLE;
/*
* First enable PAE, long mode needs it before CR0.PG = 1 is set.
@ -2411,6 +2423,12 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
bad = ctxt->ops->set_cr(ctxt, 4, cr4);
if (bad)
return X86EMUL_UNHANDLEABLE;
if (pcid) {
bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid);
if (bad)
return X86EMUL_UNHANDLEABLE;
}
}
return X86EMUL_CONTINUE;
@ -2421,11 +2439,11 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase)
struct desc_struct desc;
struct desc_ptr dt;
u16 selector;
u32 val, cr0, cr4;
u32 val, cr0, cr3, cr4;
int i;
cr0 = GET_SMSTATE(u32, smbase, 0x7ffc);
ctxt->ops->set_cr(ctxt, 3, GET_SMSTATE(u32, smbase, 0x7ff8));
cr3 = GET_SMSTATE(u32, smbase, 0x7ff8);
ctxt->eflags = GET_SMSTATE(u32, smbase, 0x7ff4) | X86_EFLAGS_FIXED;
ctxt->_eip = GET_SMSTATE(u32, smbase, 0x7ff0);
@ -2467,14 +2485,14 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase)
ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7ef8));
return rsm_enter_protected_mode(ctxt, cr0, cr4);
return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4);
}
static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
{
struct desc_struct desc;
struct desc_ptr dt;
u64 val, cr0, cr4;
u64 val, cr0, cr3, cr4;
u32 base3;
u16 selector;
int i, r;
@ -2491,7 +2509,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1);
cr0 = GET_SMSTATE(u64, smbase, 0x7f58);
ctxt->ops->set_cr(ctxt, 3, GET_SMSTATE(u64, smbase, 0x7f50));
cr3 = GET_SMSTATE(u64, smbase, 0x7f50);
cr4 = GET_SMSTATE(u64, smbase, 0x7f48);
ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7f00));
val = GET_SMSTATE(u64, smbase, 0x7ed0);
@ -2519,7 +2537,7 @@ 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);
r = rsm_enter_protected_mode(ctxt, cr0, cr4);
r = rsm_enter_protected_mode(ctxt, cr0, cr3, cr4);
if (r != X86EMUL_CONTINUE)
return r;