From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [RFC PATCH v2 28/38] KVM: arm64: Emulate EL12 register accesses from the virtual EL2 Date: Mon, 31 Jul 2017 10:44:11 +0200 Message-ID: <20170731084411.GO5176@cbox> References: <1500397144-16232-1-git-send-email-jintack.lim@linaro.org> <1500397144-16232-29-git-send-email-jintack.lim@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, david.daney@cavium.com, catalin.marinas@arm.com, will.deacon@arm.com, kvmarm@lists.cs.columbia.edu, stefan@hello-penguin.com, corbet@lwn.net, daniel.lezcano@linaro.org, linux@armlinux.org.uk, linux-arm-kernel@lists.infradead.org, andy.gross@linaro.org, marc.zyngier@arm.com, cov@codeaurora.org, wcohen@redhat.com, mchehab@kernel.org, ard.biesheuvel@linaro.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, akpm@linux-foundation.org To: Jintack Lim Return-path: Content-Disposition: inline In-Reply-To: <1500397144-16232-29-git-send-email-jintack.lim@linaro.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On Tue, Jul 18, 2017 at 11:58:54AM -0500, Jintack Lim wrote: > With HCR_EL2.NV bit set, accesses to EL12 registers in the virtual EL2 > trap to EL2. Handle those traps just like we do for EL1 registers. > > One exception is CNTKCTL_EL12. We don't trap on CNTKCTL_EL1 for non-VHE > virtual EL2 because we don't have to. However, accessing CNTKCTL_EL12 > will trap since it's one of the EL12 registers controlled by HCR_EL2.NV > bit. Therefore, add a handler for it and don't treat it as a > non-trap-registers when preparing a shadow context. I'm sorry, I don't remember the details, and I don't understand from this paragraph what the difference between CNTKCTL_EL12 and the other EL12 registers is? > > Move EL12 system register macros to a common place to reuse them. > > Signed-off-by: Jintack Lim > --- > arch/arm64/include/asm/kvm_hyp.h | 24 ------------------------ > arch/arm64/include/asm/sysreg.h | 24 ++++++++++++++++++++++++ > arch/arm64/kvm/context.c | 7 +++++++ > arch/arm64/kvm/sys_regs.c | 25 +++++++++++++++++++++++++ > 4 files changed, 56 insertions(+), 24 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h > index 4572a9b..353b895 100644 > --- a/arch/arm64/include/asm/kvm_hyp.h > +++ b/arch/arm64/include/asm/kvm_hyp.h > @@ -73,30 +73,6 @@ > #define read_sysreg_el1(r) read_sysreg_elx(r, _EL1, _EL12) > #define write_sysreg_el1(v,r) write_sysreg_elx(v, r, _EL1, _EL12) > > -/* The VHE specific system registers and their encoding */ > -#define sctlr_EL12 sys_reg(3, 5, 1, 0, 0) > -#define cpacr_EL12 sys_reg(3, 5, 1, 0, 2) > -#define ttbr0_EL12 sys_reg(3, 5, 2, 0, 0) > -#define ttbr1_EL12 sys_reg(3, 5, 2, 0, 1) > -#define tcr_EL12 sys_reg(3, 5, 2, 0, 2) > -#define afsr0_EL12 sys_reg(3, 5, 5, 1, 0) > -#define afsr1_EL12 sys_reg(3, 5, 5, 1, 1) > -#define esr_EL12 sys_reg(3, 5, 5, 2, 0) > -#define far_EL12 sys_reg(3, 5, 6, 0, 0) > -#define mair_EL12 sys_reg(3, 5, 10, 2, 0) > -#define amair_EL12 sys_reg(3, 5, 10, 3, 0) > -#define vbar_EL12 sys_reg(3, 5, 12, 0, 0) > -#define contextidr_EL12 sys_reg(3, 5, 13, 0, 1) > -#define cntkctl_EL12 sys_reg(3, 5, 14, 1, 0) > -#define cntp_tval_EL02 sys_reg(3, 5, 14, 2, 0) > -#define cntp_ctl_EL02 sys_reg(3, 5, 14, 2, 1) > -#define cntp_cval_EL02 sys_reg(3, 5, 14, 2, 2) > -#define cntv_tval_EL02 sys_reg(3, 5, 14, 3, 0) > -#define cntv_ctl_EL02 sys_reg(3, 5, 14, 3, 1) > -#define cntv_cval_EL02 sys_reg(3, 5, 14, 3, 2) > -#define spsr_EL12 sys_reg(3, 5, 4, 0, 0) > -#define elr_EL12 sys_reg(3, 5, 4, 0, 1) > - > /** > * hyp_alternate_select - Generates patchable code sequences that are > * used to switch between two implementations of a function, depending > diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h > index b01c608..b8d4d0c 100644 > --- a/arch/arm64/include/asm/sysreg.h > +++ b/arch/arm64/include/asm/sysreg.h > @@ -338,6 +338,30 @@ > #define SYS_CNTVOFF_EL2 sys_reg(3, 4, 14, 0, 3) > #define SYS_CNTHCTL_EL2 sys_reg(3, 4, 14, 1, 0) > > +/* The VHE specific system registers and their encoding */ > +#define sctlr_EL12 sys_reg(3, 5, 1, 0, 0) > +#define cpacr_EL12 sys_reg(3, 5, 1, 0, 2) > +#define ttbr0_EL12 sys_reg(3, 5, 2, 0, 0) > +#define ttbr1_EL12 sys_reg(3, 5, 2, 0, 1) > +#define tcr_EL12 sys_reg(3, 5, 2, 0, 2) > +#define afsr0_EL12 sys_reg(3, 5, 5, 1, 0) > +#define afsr1_EL12 sys_reg(3, 5, 5, 1, 1) > +#define esr_EL12 sys_reg(3, 5, 5, 2, 0) > +#define far_EL12 sys_reg(3, 5, 6, 0, 0) > +#define mair_EL12 sys_reg(3, 5, 10, 2, 0) > +#define amair_EL12 sys_reg(3, 5, 10, 3, 0) > +#define vbar_EL12 sys_reg(3, 5, 12, 0, 0) > +#define contextidr_EL12 sys_reg(3, 5, 13, 0, 1) > +#define cntkctl_EL12 sys_reg(3, 5, 14, 1, 0) > +#define cntp_tval_EL02 sys_reg(3, 5, 14, 2, 0) > +#define cntp_ctl_EL02 sys_reg(3, 5, 14, 2, 1) > +#define cntp_cval_EL02 sys_reg(3, 5, 14, 2, 2) > +#define cntv_tval_EL02 sys_reg(3, 5, 14, 3, 0) > +#define cntv_ctl_EL02 sys_reg(3, 5, 14, 3, 1) > +#define cntv_cval_EL02 sys_reg(3, 5, 14, 3, 2) > +#define spsr_EL12 sys_reg(3, 5, 4, 0, 0) > +#define elr_EL12 sys_reg(3, 5, 4, 0, 1) > + > #define SYS_SP_EL2 sys_reg(3, 6, 4, 1, 0) > > /* Common SCTLR_ELx flags. */ > diff --git a/arch/arm64/kvm/context.c b/arch/arm64/kvm/context.c > index e1bc753..f3d3398 100644 > --- a/arch/arm64/kvm/context.c > +++ b/arch/arm64/kvm/context.c > @@ -121,6 +121,13 @@ static void copy_shadow_non_trap_el1_state(struct kvm_vcpu *vcpu, bool setup) > for (i = 0; i < ARRAY_SIZE(el1_non_trap_regs); i++) { > const int sr = el1_non_trap_regs[i]; > > + /* > + * We trap on cntkctl_el12 accesses from virtual EL2 as suppose as opposed to ? > + * to not trapping on cntlctl_el1 accesses. > + */ > + if (vcpu_el2_e2h_is_set(vcpu) && sr == CNTKCTL_EL1) > + continue; > + If the guest can still access CNTHCTL_EL2 via the CNTKCTL_EL1 system regsiter access encoding without trapping, why is the don't we need to copy this here? Is the point that for a VHE guest, we don't copy vcpu_sys_reg(vcpu, CNTKCTL_EL1) to the hardware CNTKCTL_EL1, but we copy vcpu_sys_reg(vcpu, CNTHCTL_EL2) into CNTKCTL_EL1 during the world switch instead? Thanks, -Christoffer > if (setup) > s_sys_regs[sr] = vcpu_sys_reg(vcpu, sr); > else > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index b3e0cb8..2aa922c 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -905,6 +905,14 @@ static inline void access_rw(struct sys_reg_params *p, u64 *sysreg) > *sysreg = p->regval; > } > > +static bool access_cntkctl_el12(struct kvm_vcpu *vcpu, > + struct sys_reg_params *p, > + const struct sys_reg_desc *r) > +{ > + access_rw(p, &vcpu_sys_reg(vcpu, r->reg)); > + return true; > +} > + > static u64 *get_special_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *p) > { > u64 reg = sys_reg(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2); > @@ -1201,6 +1209,23 @@ static bool access_cpacr(struct kvm_vcpu *vcpu, > { SYS_DESC(SYS_CNTVOFF_EL2), trap_el2_regs, reset_val, CNTVOFF_EL2, 0 }, > { SYS_DESC(SYS_CNTHCTL_EL2), trap_el2_regs, reset_val, CNTHCTL_EL2, 0 }, > > + { SYS_DESC(sctlr_EL12), access_vm_reg, reset_val, SCTLR_EL1, 0x00C50078 }, > + { SYS_DESC(cpacr_EL12), access_cpacr, reset_val, CPACR_EL1, 0 }, > + { SYS_DESC(ttbr0_EL12), access_vm_reg, reset_unknown, TTBR0_EL1 }, > + { SYS_DESC(ttbr1_EL12), access_vm_reg, reset_unknown, TTBR1_EL1 }, > + { SYS_DESC(tcr_EL12), access_vm_reg, reset_val, TCR_EL1, 0 }, > + { SYS_DESC(spsr_EL12), access_spsr}, > + { SYS_DESC(elr_EL12), access_elr}, > + { SYS_DESC(afsr0_EL12), access_vm_reg, reset_unknown, AFSR0_EL1 }, > + { SYS_DESC(afsr1_EL12), access_vm_reg, reset_unknown, AFSR1_EL1 }, > + { SYS_DESC(esr_EL12), access_vm_reg, reset_unknown, ESR_EL1 }, > + { SYS_DESC(far_EL12), access_vm_reg, reset_unknown, FAR_EL1 }, > + { SYS_DESC(mair_EL12), access_vm_reg, reset_unknown, MAIR_EL1 }, > + { SYS_DESC(amair_EL12), access_vm_reg, reset_amair_el1, AMAIR_EL1 }, > + { SYS_DESC(vbar_EL12), access_vbar, reset_val, VBAR_EL1, 0 }, > + { SYS_DESC(contextidr_EL12), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 }, > + { SYS_DESC(cntkctl_EL12), access_cntkctl_el12, reset_val, CNTKCTL_EL1, 0 }, > + > { SYS_DESC(SYS_SP_EL2), NULL, reset_special, SP_EL2, 0}, > }; > > -- > 1.9.1 >