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KVM: PPC: Book3S HV: Save/restore XER in checkpointed register state 

When switching from/to a guest that has a transaction in progress,
we need to save/restore the checkpointed register state.  Although
XER is part of the CPU state that gets checkpointed, the code that
does this saving and restoring doesn't save/restore XER.

This fixes it by saving and restoring the XER.  To allow userspace
to read/write the checkpointed XER value, we also add a new ONE_REG
specifier.

The visible effect of this bug is that the guest may see its XER
value being corrupted when it uses transactions.

Fixes: e4e3812150 ("KVM: PPC: Book3S HV: Add transactional memory support")
Fixes: 0a8eccefcb ("KVM: PPC: Book3S HV: Add missing code for transaction reclaim on guest exit")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
hifive-unleashed-5.1
Paul Mackerras 2016-11-07 15:09:58 +11:00
parent a56ee9f8f0
commit 0d808df06a
6 changed files with 14 additions and 0 deletions
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1
Documentation/virtual/kvm/api.txt
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@ -2039,6 +2039,7 @@ registers, find a list below:
PPC | KVM_REG_PPC_TM_VSCR | 32
PPC | KVM_REG_PPC_TM_DSCR | 64
PPC | KVM_REG_PPC_TM_TAR | 64
PPC | KVM_REG_PPC_TM_XER | 64
| |
MIPS | KVM_REG_MIPS_R0 | 64
...

1
arch/powerpc/include/asm/kvm_host.h
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@ -565,6 +565,7 @@ struct kvm_vcpu_arch {
u64 tfiar;
u32 cr_tm;
u64 xer_tm;
u64 lr_tm;
u64 ctr_tm;
u64 amr_tm;

1
arch/powerpc/include/uapi/asm/kvm.h
View File

@ -596,6 +596,7 @@ struct kvm_get_htab_header {
#define KVM_REG_PPC_TM_VSCR (KVM_REG_PPC_TM | KVM_REG_SIZE_U32 | 0x67)
#define KVM_REG_PPC_TM_DSCR (KVM_REG_PPC_TM | KVM_REG_SIZE_U64 | 0x68)
#define KVM_REG_PPC_TM_TAR (KVM_REG_PPC_TM | KVM_REG_SIZE_U64 | 0x69)
#define KVM_REG_PPC_TM_XER (KVM_REG_PPC_TM | KVM_REG_SIZE_U64 | 0x6a)
/* PPC64 eXternal Interrupt Controller Specification */
#define KVM_DEV_XICS_GRP_SOURCES 1 /* 64-bit source attributes */

1
arch/powerpc/kernel/asm-offsets.c
View File

@ -569,6 +569,7 @@ int main(void)
DEFINE(VCPU_VRS_TM, offsetof(struct kvm_vcpu, arch.vr_tm.vr));
DEFINE(VCPU_VRSAVE_TM, offsetof(struct kvm_vcpu, arch.vrsave_tm));
DEFINE(VCPU_CR_TM, offsetof(struct kvm_vcpu, arch.cr_tm));
DEFINE(VCPU_XER_TM, offsetof(struct kvm_vcpu, arch.xer_tm));
DEFINE(VCPU_LR_TM, offsetof(struct kvm_vcpu, arch.lr_tm));
DEFINE(VCPU_CTR_TM, offsetof(struct kvm_vcpu, arch.ctr_tm));
DEFINE(VCPU_AMR_TM, offsetof(struct kvm_vcpu, arch.amr_tm));

6
arch/powerpc/kvm/book3s_hv.c
View File

@ -1288,6 +1288,9 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
case KVM_REG_PPC_TM_CR:
*val = get_reg_val(id, vcpu->arch.cr_tm);
break;
case KVM_REG_PPC_TM_XER:
*val = get_reg_val(id, vcpu->arch.xer_tm);
break;
case KVM_REG_PPC_TM_LR:
*val = get_reg_val(id, vcpu->arch.lr_tm);
break;
@ -1498,6 +1501,9 @@ static int kvmppc_set_one_reg_hv(struct kvm_vcpu *vcpu, u64 id,
case KVM_REG_PPC_TM_CR:
vcpu->arch.cr_tm = set_reg_val(id, *val);
break;
case KVM_REG_PPC_TM_XER:
vcpu->arch.xer_tm = set_reg_val(id, *val);
break;
case KVM_REG_PPC_TM_LR:
vcpu->arch.lr_tm = set_reg_val(id, *val);
break;

4
arch/powerpc/kvm/book3s_hv_rmhandlers.S
View File

@ -2600,11 +2600,13 @@ kvmppc_save_tm:
mfctr r7
mfspr r8, SPRN_AMR
mfspr r10, SPRN_TAR
mfxer r11
std r5, VCPU_LR_TM(r9)
stw r6, VCPU_CR_TM(r9)
std r7, VCPU_CTR_TM(r9)
std r8, VCPU_AMR_TM(r9)
std r10, VCPU_TAR_TM(r9)
std r11, VCPU_XER_TM(r9)
/* Restore r12 as trap number. */
lwz r12, VCPU_TRAP(r9)
@ -2697,11 +2699,13 @@ kvmppc_restore_tm:
ld r7, VCPU_CTR_TM(r4)
ld r8, VCPU_AMR_TM(r4)
ld r9, VCPU_TAR_TM(r4)
ld r10, VCPU_XER_TM(r4)
mtlr r5
mtcr r6
mtctr r7
mtspr SPRN_AMR, r8
mtspr SPRN_TAR, r9
mtxer r10
/*
* Load up PPR and DSCR values but don't put them in the actual SPRs