From 8e6afa36e754be84b468d7df9e5aa71cf4003f3b Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 31 Jul 2014 10:21:59 +0200 Subject: [PATCH] KVM: PPC: PR: Handle FSCR feature deselects We handle FSCR feature bits (well, TAR only really today) lazily when the guest starts using them. So when a guest activates the bit and later uses that feature we enable it for real in hardware. However, when the guest stops using that bit we don't stop setting it in hardware. That means we can potentially lose a trap that the guest expects to happen because it thinks a feature is not active. This patch adds support to drop TAR when then guest turns it off in FSCR. While at it it also restricts FSCR access to 64bit systems - 32bit ones don't have it. Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/kvm_book3s.h | 1 + arch/powerpc/kvm/book3s_emulate.c | 6 +++--- arch/powerpc/kvm/book3s_pr.c | 9 +++++++++ 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 61667913ec98..6acf0c2a0f99 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -182,6 +182,7 @@ extern long kvmppc_hv_get_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot, unsigned long *map); 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); extern void kvmppc_entry_trampoline(void); extern void kvmppc_hv_entry_trampoline(void); diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c index 84fddcd6c1f8..5a2bc4b0dfe5 100644 --- a/arch/powerpc/kvm/book3s_emulate.c +++ b/arch/powerpc/kvm/book3s_emulate.c @@ -449,10 +449,10 @@ int kvmppc_core_emulate_mtspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val) case SPRN_GQR7: to_book3s(vcpu)->gqr[sprn - SPRN_GQR0] = spr_val; break; +#ifdef CONFIG_PPC_BOOK3S_64 case SPRN_FSCR: - vcpu->arch.fscr = spr_val; + kvmppc_set_fscr(vcpu, spr_val); break; -#ifdef CONFIG_PPC_BOOK3S_64 case SPRN_BESCR: vcpu->arch.bescr = spr_val; break; @@ -593,10 +593,10 @@ int kvmppc_core_emulate_mfspr_pr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val case SPRN_GQR7: *spr_val = to_book3s(vcpu)->gqr[sprn - SPRN_GQR0]; break; +#ifdef CONFIG_PPC_BOOK3S_64 case SPRN_FSCR: *spr_val = vcpu->arch.fscr; break; -#ifdef CONFIG_PPC_BOOK3S_64 case SPRN_BESCR: *spr_val = vcpu->arch.bescr; break; diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index e7a1fa2517b1..faffb27badd9 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -871,6 +871,15 @@ static int kvmppc_handle_fac(struct kvm_vcpu *vcpu, ulong fac) return RESUME_GUEST; } + +void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr) +{ + if ((vcpu->arch.fscr & FSCR_TAR) && !(fscr & FSCR_TAR)) { + /* TAR got dropped, drop it in shadow too */ + kvmppc_giveup_fac(vcpu, FSCR_TAR_LG); + } + vcpu->arch.fscr = fscr; +} #endif int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, -- 2.45.2