This is a note to let you know that I've just added the patch titled

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

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: kvm-x86-fix-rsm-when-pcid-is-non-zero.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From fae1a3e775cca8c3a9e0eb34443b310871a15a92 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini pbonzini@redhat.com Date: Thu, 21 Dec 2017 00:49:14 +0100 Subject: kvm: x86: fix RSM when PCID is non-zero

From: Paolo Bonzini pbonzini@redhat.com

commit fae1a3e775cca8c3a9e0eb34443b310871a15a92 upstream.

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: 660a5d517aaab9187f93854425c4c63f4a09195c Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/x86/kvm/emulate.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-)

--- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2395,9 +2395,21 @@ static int rsm_load_seg_64(struct x86_em }

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. @@ -2416,6 +2428,12 @@ static int rsm_enter_protected_mode(stru 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; @@ -2426,11 +2444,11 @@ static int rsm_load_state_32(struct x86_ 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);

@@ -2472,14 +2490,14 @@ static int rsm_load_state_32(struct x86_

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; @@ -2496,7 +2514,7 @@ static int rsm_load_state_64(struct x86_ 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); @@ -2524,7 +2542,7 @@ static int rsm_load_state_64(struct x86_ 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;

Patches currently in stable-queue which might be from pbonzini@redhat.com are

queue-4.9/kvm-x86-fix-load-rflags-w-o-the-fixed-bit.patch queue-4.9/kvm-x86-fix-rsm-when-pcid-is-non-zero.patch