From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [RFC PATCH v2 08/38] KVM: arm64: Add EL2 special registers to vcpu context Date: Sun, 30 Jul 2017 21:59:55 +0200 Message-ID: <20170730195955.GG5176@cbox> References: <1500397144-16232-1-git-send-email-jintack.lim@linaro.org> <1500397144-16232-9-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: <1500397144-16232-9-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 11:58:34AM -0500, Jintack Lim wrote: > To support the virtual EL2 execution, we need to maintain the EL2 > special registers such as SPSR_EL2, ELR_EL2 and SP_EL2 in vcpu context. > > Note that SP_EL2 is not accessible in EL2, so we don't need a trap > handler for this register. Actually, it's not accessible *in the MRS/MSR instruction* but it is of course accessible as the current stack pointer (which is why you need the state, but not the trap handler). Otherwise, the patch looks good. Thanks, -Christoffer > > Signed-off-by: Jintack Lim > --- > arch/arm64/include/asm/kvm_host.h | 12 ++++++++++++ > arch/arm64/include/asm/sysreg.h | 4 ++++ > arch/arm64/kvm/sys_regs.c | 38 +++++++++++++++++++++++++++++++++----- > arch/arm64/kvm/sys_regs.h | 8 ++++++++ > 4 files changed, 57 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 1dc4ed6..57dccde 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -171,6 +171,15 @@ enum vcpu_sysreg { > NR_SYS_REGS /* Nothing after this line! */ > }; > > +enum el2_special_regs { > + __INVALID_EL2_SPECIAL_REG__, > + SPSR_EL2, /* Saved Program Status Register (EL2) */ > + ELR_EL2, /* Exception Link Register (EL2) */ > + SP_EL2, /* Stack Pointer (EL2) */ > + > + NR_EL2_SPECIAL_REGS > +}; > + > /* 32bit mapping */ > #define c0_MPIDR (MPIDR_EL1 * 2) /* MultiProcessor ID Register */ > #define c0_CSSELR (CSSELR_EL1 * 2)/* Cache Size Selection Register */ > @@ -218,6 +227,8 @@ struct kvm_cpu_context { > u64 sys_regs[NR_SYS_REGS]; > u32 copro[NR_COPRO_REGS]; > }; > + > + u64 el2_special_regs[NR_EL2_SPECIAL_REGS]; > }; > > typedef struct kvm_cpu_context kvm_cpu_context_t; > @@ -307,6 +318,7 @@ struct kvm_vcpu_arch { > > #define vcpu_gp_regs(v) (&(v)->arch.ctxt.gp_regs) > #define vcpu_sys_reg(v,r) ((v)->arch.ctxt.sys_regs[(r)]) > +#define vcpu_el2_sreg(v,r) ((v)->arch.ctxt.el2_special_regs[(r)]) > /* > * CP14 and CP15 live in the same array, as they are backed by the > * same system registers. > diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h > index 9277c4a..98c32ef 100644 > --- a/arch/arm64/include/asm/sysreg.h > +++ b/arch/arm64/include/asm/sysreg.h > @@ -268,6 +268,8 @@ > > #define SYS_DACR32_EL2 sys_reg(3, 4, 3, 0, 0) > > +#define SYS_SPSR_EL2 sys_reg(3, 4, 4, 0, 0) > +#define SYS_ELR_EL2 sys_reg(3, 4, 4, 0, 1) > #define SYS_SP_EL1 sys_reg(3, 4, 4, 1, 0) > > #define SYS_IFSR32_EL2 sys_reg(3, 4, 5, 0, 1) > @@ -332,6 +334,8 @@ > #define SYS_CNTVOFF_EL2 sys_reg(3, 4, 14, 0, 3) > #define SYS_CNTHCTL_EL2 sys_reg(3, 4, 14, 1, 0) > > +#define SYS_SP_EL2 sys_reg(3, 6, 4, 1, 0) > + > /* Common SCTLR_ELx flags. */ > #define SCTLR_ELx_EE (1 << 25) > #define SCTLR_ELx_I (1 << 12) > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 1568f8b..2b3ed70 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -900,15 +900,33 @@ static inline void access_rw(struct sys_reg_params *p, u64 *sysreg) > *sysreg = p->regval; > } > > +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); > + > + switch (reg) { > + case SYS_SP_EL1: > + return &vcpu->arch.ctxt.gp_regs.sp_el1; > + case SYS_ELR_EL2: > + return &vcpu_el2_sreg(vcpu, ELR_EL2); > + case SYS_SPSR_EL2: > + return &vcpu_el2_sreg(vcpu, SPSR_EL2); > + default: > + return NULL; > + }; > +} > + > static bool trap_el2_regs(struct kvm_vcpu *vcpu, > struct sys_reg_params *p, > const struct sys_reg_desc *r) > { > - /* SP_EL1 is NOT maintained in sys_regs array */ > - if (sys_reg(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2) == SYS_SP_EL1) > - access_rw(p, &vcpu->arch.ctxt.gp_regs.sp_el1); > - else > - access_rw(p, &vcpu_sys_reg(vcpu, r->reg)); > + u64 *sys_reg; > + > + sys_reg = get_special_reg(vcpu, p); > + if (!sys_reg) > + sys_reg = &vcpu_sys_reg(vcpu, r->reg); > + > + access_rw(p, sys_reg); > > return true; > } > @@ -1116,6 +1134,8 @@ static bool trap_el2_regs(struct kvm_vcpu *vcpu, > > { SYS_DESC(SYS_DACR32_EL2), NULL, reset_unknown, DACR32_EL2 }, > > + { SYS_DESC(SYS_SPSR_EL2), trap_el2_regs, reset_special, SPSR_EL2, 0 }, > + { SYS_DESC(SYS_ELR_EL2), trap_el2_regs, reset_special, ELR_EL2, 0 }, > { SYS_DESC(SYS_SP_EL1), trap_el2_regs }, > > { SYS_DESC(SYS_IFSR32_EL2), NULL, reset_unknown, IFSR32_EL2 }, > @@ -1138,6 +1158,8 @@ static bool trap_el2_regs(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(SYS_SP_EL2), NULL, reset_special, SP_EL2, 0}, > }; > > static bool trap_dbgidr(struct kvm_vcpu *vcpu, > @@ -2271,6 +2293,8 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu) > > /* Catch someone adding a register without putting in reset entry. */ > memset(&vcpu->arch.ctxt.sys_regs, 0x42, sizeof(vcpu->arch.ctxt.sys_regs)); > + memset(&vcpu->arch.ctxt.el2_special_regs, 0x42, > + sizeof(vcpu->arch.ctxt.el2_special_regs)); > > /* Generic chip reset first (so target could override). */ > reset_sys_reg_descs(vcpu, sys_reg_descs, ARRAY_SIZE(sys_reg_descs)); > @@ -2281,4 +2305,8 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu) > for (num = 1; num < NR_SYS_REGS; num++) > if (vcpu_sys_reg(vcpu, num) == 0x4242424242424242) > panic("Didn't reset vcpu_sys_reg(%zi)", num); > + > + for (num = 1; num < NR_EL2_SPECIAL_REGS; num++) > + if (vcpu_el2_sreg(vcpu, num) == 0x4242424242424242) > + panic("Didn't reset vcpu_el2_sreg(%zi)", num); > } > diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h > index 060f534..827717b 100644 > --- a/arch/arm64/kvm/sys_regs.h > +++ b/arch/arm64/kvm/sys_regs.h > @@ -99,6 +99,14 @@ static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r > vcpu_sys_reg(vcpu, r->reg) = r->val; > } > > +static inline void reset_special(struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *r) > +{ > + BUG_ON(!r->reg); > + BUG_ON(r->reg >= NR_EL2_SPECIAL_REGS); > + vcpu_el2_sreg(vcpu, r->reg) = r->val; > +} > + > static inline int cmp_sys_reg(const struct sys_reg_desc *i1, > const struct sys_reg_desc *i2) > { > -- > 1.9.1 >