Guest LPCR depends on hardware type, and future changes will add
restrictions based on errata and guest MMU mode. Move this logic
to a common function and use it for the cases where the guest
wants to update its LPCR (or the LPCR of a nested guest).
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
arch/powerpc/include/asm/kvm_book3s.h | 2 +
arch/powerpc/kvm/book3s_hv.c | 60 ++++++++++++++++++---------
arch/powerpc/kvm/book3s_hv_nested.c | 3 +-
3 files changed, 45 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 2f5f919f6cd3..3eec3ef6f083 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -258,6 +258,8 @@ extern long kvmppc_hv_get_dirty_log_hpt(struct kvm *kvm,
extern void kvmppc_harvest_vpa_dirty(struct kvmppc_vpa *vpa,
struct kvm_memory_slot *memslot,
unsigned long *map);
+extern unsigned long kvmppc_filter_lpcr_hv(struct kvmppc_vcore *vc,
+ unsigned long lpcr);
extern void kvmppc_update_lpcr(struct kvm *kvm, unsigned long lpcr,
unsigned long mask);
extern void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr);
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 13bad6bf4c95..c4539c38c639 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1635,6 +1635,27 @@ static int kvm_arch_vcpu_ioctl_set_sregs_hv(struct kvm_vcpu *vcpu,
return 0;
}
+/*
+ * Enforce limits on guest LPCR values based on hardware availability,
+ * guest configuration, and possibly hypervisor support and security
+ * concerns.
+ */
+unsigned long kvmppc_filter_lpcr_hv(struct kvmppc_vcore *vc, unsigned long lpcr)
+{
+ /* On POWER8 and above, userspace can modify AIL */
+ if (!cpu_has_feature(CPU_FTR_ARCH_207S))
+ lpcr &= ~LPCR_AIL;
+
+ /*
+ * On POWER9, allow userspace to enable large decrementer for the
+ * guest, whether or not the host has it enabled.
+ */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ lpcr &= ~LPCR_LD;
+
+ return lpcr;
+}
+
static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr,
bool preserve_top32)
{
@@ -1643,6 +1664,23 @@ static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr,
u64 mask;
spin_lock(&vc->lock);
+
+ /*
+ * Userspace can only modify
+ * DPFD (default prefetch depth), ILE (interrupt little-endian),
+ * TC (translation control), AIL (alternate interrupt location),
+ * LD (large decrementer).
+ * These are subject to restrictions from kvmppc_filter_lcpr_hv().
+ */
+ mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD;
+
+ /* Broken 32-bit version of LPCR must not clear top bits */
+ if (preserve_top32)
+ mask &= 0xFFFFFFFF;
+
+ new_lpcr = kvmppc_filter_lpcr_hv(vc,
+ (vc->lpcr & ~mask) | (new_lpcr & mask));
+
/*
* If ILE (interrupt little-endian) has changed, update the
* MSR_LE bit in the intr_msr for each vcpu in this vcore.
@@ -1661,25 +1699,8 @@ static void kvmppc_set_lpcr(struct kvm_vcpu *vcpu, u64 new_lpcr,
}
}
- /*
- * Userspace can only modify DPFD (default prefetch depth),
- * ILE (interrupt little-endian) and TC (translation control).
- * On POWER8 and POWER9 userspace can also modify AIL (alt. interrupt loc.).
- */
- mask = LPCR_DPFD | LPCR_ILE | LPCR_TC;
- if (cpu_has_feature(CPU_FTR_ARCH_207S))
- mask |= LPCR_AIL;
- /*
- * On POWER9, allow userspace to enable large decrementer for the
- * guest, whether or not the host has it enabled.
- */
- if (cpu_has_feature(CPU_FTR_ARCH_300))
- mask |= LPCR_LD;
+ vc->lpcr = new_lpcr;
- /* Broken 32-bit version of LPCR must not clear top bits */
- if (preserve_top32)
- mask &= 0xFFFFFFFF;
- vc->lpcr = (vc->lpcr & ~mask) | (new_lpcr & mask);
spin_unlock(&vc->lock);
}
@@ -4641,8 +4662,9 @@ void kvmppc_update_lpcr(struct kvm *kvm, unsigned long lpcr, unsigned long mask)
struct kvmppc_vcore *vc = kvm->arch.vcores[i];
if (!vc)
continue;
+
spin_lock(&vc->lock);
- vc->lpcr = (vc->lpcr & ~mask) | lpcr;
+ vc->lpcr = kvmppc_filter_lpcr_hv(vc, (vc->lpcr & ~mask) | lpcr);
spin_unlock(&vc->lock);
if (++cores_done >= kvm->arch.online_vcores)
break;
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 2fe1fea4c934..f7b441b3eb17 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -142,7 +142,8 @@ static void sanitise_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr)
*/
mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD |
LPCR_LPES | LPCR_MER;
- hr->lpcr = (vc->lpcr & ~mask) | (hr->lpcr & mask);
+ hr->lpcr = kvmppc_filter_lpcr_hv(vc,
+ (vc->lpcr & ~mask) | (hr->lpcr & mask));
/*
* Don't let L1 enable features for L2 which we've disabled for L1,
--
2.23.0
