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Wed, 31 Mar 2021 15:34:48 +1100 (AEDT) Received: by ozlabs.org (Postfix, from userid 1003) id 4F9D4R57SWz9sWK; Wed, 31 Mar 2021 15:34:47 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ozlabs.org; s=201707; t=1617165287; bh=M8wBblT1g1uK1hduyoudLisyaXN7+YXCuqNzj9Dhb/g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=viee5o80vBg3ho5ACESOQ+9T1l4UA7qgWjYMS0IsH7WLxihifZO9EDgZvp7iCQn/P kLO5oM+SJTWXpP2NVSm/sTLQ2xf9OPFgwRDxmafsp0Qac7esRneKzqeVjCZSDBqvhZ UyTqydirhtL3ttvod6DUf2DNgFWHu/g98O7R2obc5rSGsxWJgvPs17Vnifv5IRmf00 yKfEH/czMg/zX50H2q8wR39y5n/ZcChWuXjGsK2Wp0CJBKaRARxplrKUBivpIP2UuP HrDSuYsKHtkNhtqsCU1Vd/x8/+pyaXP0tsMxPXh/lV4QWdMy7UJ9c6Gy0g9AJOasS1 pJKsrFc8TPsYg== Date: Wed, 31 Mar 2021 15:34:41 +1100 From: Paul Mackerras To: Nicholas Piggin Subject: Re: [PATCH v4 04/46] KVM: PPC: Book3S HV: Prevent radix guests from setting LPCR[TC] Message-ID: References: <20210323010305.1045293-1-npiggin@gmail.com> <20210323010305.1045293-5-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210323010305.1045293-5-npiggin@gmail.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, Mar 23, 2021 at 11:02:23AM +1000, Nicholas Piggin wrote: > This bit only applies to hash partitions. > > Signed-off-by: Nicholas Piggin > --- > arch/powerpc/kvm/book3s_hv.c | 6 ++++++ > arch/powerpc/kvm/book3s_hv_nested.c | 3 +-- > 2 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > index c5de7e3f22b6..1ffb0902e779 100644 > --- a/arch/powerpc/kvm/book3s_hv.c > +++ b/arch/powerpc/kvm/book3s_hv.c > @@ -1645,6 +1645,12 @@ static int kvm_arch_vcpu_ioctl_set_sregs_hv(struct kvm_vcpu *vcpu, > */ > unsigned long kvmppc_filter_lpcr_hv(struct kvmppc_vcore *vc, unsigned long lpcr) > { > + struct kvm *kvm = vc->kvm; > + > + /* LPCR_TC only applies to HPT guests */ > + if (kvm_is_radix(kvm)) > + lpcr &= ~LPCR_TC; I'm not sure I see any benefit from this, and it is a little extra complexity. > /* On POWER8 and above, userspace can modify AIL */ > if (!cpu_has_feature(CPU_FTR_ARCH_207S)) > lpcr &= ~LPCR_AIL; > diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c > index f7b441b3eb17..851e3f527eb2 100644 > --- a/arch/powerpc/kvm/book3s_hv_nested.c > +++ b/arch/powerpc/kvm/book3s_hv_nested.c > @@ -140,8 +140,7 @@ static void sanitise_hv_regs(struct kvm_vcpu *vcpu, struct hv_guest_state *hr) > /* > * Don't let L1 change LPCR bits for the L2 except these: > */ > - mask = LPCR_DPFD | LPCR_ILE | LPCR_TC | LPCR_AIL | LPCR_LD | > - LPCR_LPES | LPCR_MER; > + mask = LPCR_DPFD | LPCR_ILE | LPCR_AIL | LPCR_LD | LPCR_LPES | LPCR_MER; Doesn't this make it completely impossible to set TC for any guest? Paul.