Re: [PATCH 07/59] KVM: arm64: nv: Add EL2 system registers to vcpu context

Alexandru Elisei
2019-06-24T15:47:58Z

On 6/21/19 10:37 AM, Marc Zyngier wrote:
> From: Jintack Lim <jintack.lim@linaro.org>
>
> ARM v8.3 introduces a new bit in the HCR_EL2, which is the NV bit. When
> this bit is set, accessing EL2 registers in EL1 traps to EL2. In
> addition, executing the following instructions in EL1 will trap to EL2:
> tlbi, at, eret, and msr/mrs instructions to access SP_EL1. Most of the
> instructions that trap to EL2 with the NV bit were undef at EL1 prior to
> ARM v8.3. The only instruction that was not undef is eret.
>
> This patch sets up a handler for EL2 registers and SP_EL1 register
> accesses at EL1. The host hypervisor keeps those register values in
> memory, and will emulate their behavior.
>
> This patch doesn't set the NV bit yet. It will be set in a later patch
> once nested virtualization support is completed.
>
> Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 37 +++++++++++++++-
> arch/arm64/include/asm/sysreg.h | 50 ++++++++++++++++++++-
> arch/arm64/kvm/sys_regs.c | 74 ++++++++++++++++++++++++++++---
> 3 files changed, 154 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 4bcd9c1291d5..2d4290d2513a 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -173,12 +173,47 @@ enum vcpu_sysreg {
> APGAKEYLO_EL1,
> APGAKEYHI_EL1,
>
> - /* 32bit specific registers. Keep them at the end of the range */
> + /* 32bit specific registers. */
> DACR32_EL2, /* Domain Access Control Register */
> IFSR32_EL2, /* Instruction Fault Status Register */
> FPEXC32_EL2, /* Floating-Point Exception Control Register */
> DBGVCR32_EL2, /* Debug Vector Catch Register */
>
> + /* EL2 registers sorted ascending by Op0, Op1, CRn, CRm, Op2 */
> + FIRST_EL2_SYSREG,
> + VPIDR_EL2 = FIRST_EL2_SYSREG,
> + /* Virtualization Processor ID Register */
> + VMPIDR_EL2, /* Virtualization Multiprocessor ID Register */
> + SCTLR_EL2, /* System Control Register (EL2) */
> + ACTLR_EL2, /* Auxiliary Control Register (EL2) */
> + HCR_EL2, /* Hypervisor Configuration Register */
> + MDCR_EL2, /* Monitor Debug Configuration Register (EL2) */
> + CPTR_EL2, /* Architectural Feature Trap Register (EL2) */
> + HSTR_EL2, /* Hypervisor System Trap Register */
> + HACR_EL2, /* Hypervisor Auxiliary Control Register */
> + TTBR0_EL2, /* Translation Table Base Register 0 (EL2) */
> + TTBR1_EL2, /* Translation Table Base Register 1 (EL2) */
> + TCR_EL2, /* Translation Control Register (EL2) */
> + VTTBR_EL2, /* Virtualization Translation Table Base Register */
> + VTCR_EL2, /* Virtualization Translation Control Register */
> + SPSR_EL2, /* EL2 saved program status register */
> + ELR_EL2, /* EL2 exception link register */
> + AFSR0_EL2, /* Auxiliary Fault Status Register 0 (EL2) */
> + AFSR1_EL2, /* Auxiliary Fault Status Register 1 (EL2) */
> + ESR_EL2, /* Exception Syndrome Register (EL2) */
> + FAR_EL2, /* Hypervisor IPA Fault Address Register */
> + HPFAR_EL2, /* Hypervisor IPA Fault Address Register */
> + MAIR_EL2, /* Memory Attribute Indirection Register (EL2) */
> + AMAIR_EL2, /* Auxiliary Memory Attribute Indirection Register (EL2) */
> + VBAR_EL2, /* Vector Base Address Register (EL2) */
> + RVBAR_EL2, /* Reset Vector Base Address Register */
> + RMR_EL2, /* Reset Management Register */
> + CONTEXTIDR_EL2, /* Context ID Register (EL2) */
> + TPIDR_EL2, /* EL2 Software Thread ID Register */
> + CNTVOFF_EL2, /* Counter-timer Virtual Offset register */
> + CNTHCTL_EL2, /* Counter-timer Hypervisor Control register */
> + SP_EL2, /* EL2 Stack Pointer */
> +
> NR_SYS_REGS /* Nothing after this line! */
> };
>
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index f3ca7e4796ab..8b95f2c42c3d 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -411,17 +411,49 @@
>
> #define SYS_PMCCFILTR_EL0 sys_reg(3, 3, 14, 15, 7)
>
> +#define SYS_VPIDR_EL2 sys_reg(3, 4, 0, 0, 0)
> +#define SYS_VMPIDR_EL2 sys_reg(3, 4, 0, 0, 5)
> +
> +#define SYS_SCTLR_EL2 sys_reg(3, 4, 1, 0, 0)
> +#define SYS_ACTLR_EL2 sys_reg(3, 4, 1, 0, 1)
> +#define SYS_HCR_EL2 sys_reg(3, 4, 1, 1, 0)
> +#define SYS_MDCR_EL2 sys_reg(3, 4, 1, 1, 1)
> +#define SYS_CPTR_EL2 sys_reg(3, 4, 1, 1, 2)
> +#define SYS_HSTR_EL2 sys_reg(3, 4, 1, 1, 3)
> +#define SYS_HACR_EL2 sys_reg(3, 4, 1, 1, 7)
> +
> #define SYS_ZCR_EL2 sys_reg(3, 4, 1, 2, 0)
> +
> +#define SYS_TTBR0_EL2 sys_reg(3, 4, 2, 0, 0)
> +#define SYS_TTBR1_EL2 sys_reg(3, 4, 2, 0, 1)
> +#define SYS_TCR_EL2 sys_reg(3, 4, 2, 0, 2)
> +#define SYS_VTTBR_EL2 sys_reg(3, 4, 2, 1, 0)
> +#define SYS_VTCR_EL2 sys_reg(3, 4, 2, 1, 2)
> +
> #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)
> +#define SYS_AFSR0_EL2 sys_reg(3, 4, 5, 1, 0)
> +#define SYS_AFSR1_EL2 sys_reg(3, 4, 5, 1, 1)
> #define SYS_ESR_EL2 sys_reg(3, 4, 5, 2, 0)
> #define SYS_VSESR_EL2 sys_reg(3, 4, 5, 2, 3)
> #define SYS_FPEXC32_EL2 sys_reg(3, 4, 5, 3, 0)
> #define SYS_FAR_EL2 sys_reg(3, 4, 6, 0, 0)
>
> -#define SYS_VDISR_EL2 sys_reg(3, 4, 12, 1, 1)
> +#define SYS_FAR_EL2 sys_reg(3, 4, 6, 0, 0)
> +#define SYS_HPFAR_EL2 sys_reg(3, 4, 6, 0, 4)
> +
> +#define SYS_MAIR_EL2 sys_reg(3, 4, 10, 2, 0)
> +#define SYS_AMAIR_EL2 sys_reg(3, 4, 10, 3, 0)
> +
> +#define SYS_VBAR_EL2 sys_reg(3, 4, 12, 0, 0)
> +#define SYS_RVBAR_EL2 sys_reg(3, 4, 12, 0, 1)
> +#define SYS_RMR_EL2 sys_reg(3, 4, 12, 0, 2)
> +#define SYS_VDISR_EL2 sys_reg(3, 4, 12, 1, 1)
> #define __SYS__AP0Rx_EL2(x) sys_reg(3, 4, 12, 8, x)
> #define SYS_ICH_AP0R0_EL2 __SYS__AP0Rx_EL2(0)
> #define SYS_ICH_AP0R1_EL2 __SYS__AP0Rx_EL2(1)
> @@ -463,23 +495,37 @@
> #define SYS_ICH_LR14_EL2 __SYS__LR8_EL2(6)
> #define SYS_ICH_LR15_EL2 __SYS__LR8_EL2(7)
>
> +#define SYS_CONTEXTIDR_EL2 sys_reg(3, 4, 13, 0, 1)
> +#define SYS_TPIDR_EL2 sys_reg(3, 4, 13, 0, 2)
> +
> +#define SYS_CNTVOFF_EL2 sys_reg(3, 4, 14, 0, 3)
> +#define SYS_CNTHCTL_EL2 sys_reg(3, 4, 14, 1, 0)
> +
> /* VHE encodings for architectural EL0/1 system registers */
> #define SYS_SCTLR_EL12 sys_reg(3, 5, 1, 0, 0)
> #define SYS_CPACR_EL12 sys_reg(3, 5, 1, 0, 2)
> #define SYS_ZCR_EL12 sys_reg(3, 5, 1, 2, 0)
> +
> #define SYS_TTBR0_EL12 sys_reg(3, 5, 2, 0, 0)
> #define SYS_TTBR1_EL12 sys_reg(3, 5, 2, 0, 1)
> #define SYS_TCR_EL12 sys_reg(3, 5, 2, 0, 2)
> +
> #define SYS_SPSR_EL12 sys_reg(3, 5, 4, 0, 0)
> #define SYS_ELR_EL12 sys_reg(3, 5, 4, 0, 1)
> +
> #define SYS_AFSR0_EL12 sys_reg(3, 5, 5, 1, 0)
> #define SYS_AFSR1_EL12 sys_reg(3, 5, 5, 1, 1)
> #define SYS_ESR_EL12 sys_reg(3, 5, 5, 2, 0)
> +
> #define SYS_FAR_EL12 sys_reg(3, 5, 6, 0, 0)
> +
> #define SYS_MAIR_EL12 sys_reg(3, 5, 10, 2, 0)
> #define SYS_AMAIR_EL12 sys_reg(3, 5, 10, 3, 0)
> +
> #define SYS_VBAR_EL12 sys_reg(3, 5, 12, 0, 0)
> +
> #define SYS_CONTEXTIDR_EL12 sys_reg(3, 5, 13, 0, 1)
> +
> #define SYS_CNTKCTL_EL12 sys_reg(3, 5, 14, 1, 0)
> #define SYS_CNTP_TVAL_EL02 sys_reg(3, 5, 14, 2, 0)
> #define SYS_CNTP_CTL_EL02 sys_reg(3, 5, 14, 2, 1)
> @@ -488,6 +534,8 @@
> #define SYS_CNTV_CTL_EL02 sys_reg(3, 5, 14, 3, 1)
> #define SYS_CNTV_CVAL_EL02 sys_reg(3, 5, 14, 3, 2)
>
> +#define SYS_SP_EL2 sys_reg(3, 6, 4, 1, 0)
> +
> /* Common SCTLR_ELx flags. */
> #define SCTLR_ELx_DSSBS (_BITUL(44))
> #define SCTLR_ELx_ENIA (_BITUL(31))
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index adb8a7e9c8e4..e81be6debe07 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -184,6 +184,18 @@ static u32 get_ccsidr(u32 csselr)
> return ccsidr;
> }
>
> +static bool access_rw(struct kvm_vcpu *vcpu,
> + struct sys_reg_params *p,
> + const struct sys_reg_desc *r)
> +{
> + if (p->is_write)
> + vcpu_write_sys_reg(vcpu, p->regval, r->reg);
> + else
> + p->regval = vcpu_read_sys_reg(vcpu, r->reg);
> +
> + return true;
> +}
> +
> /*
> * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
> */
> @@ -394,12 +406,9 @@ static bool trap_debug_regs(struct kvm_vcpu *vcpu,
> struct sys_reg_params *p,
> const struct sys_reg_desc *r)
> {
> - if (p->is_write) {
> - vcpu_write_sys_reg(vcpu, p->regval, r->reg);
> + access_rw(vcpu, p, r);
> + if (p->is_write)
> vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY;
> - } else {
> - p->regval = vcpu_read_sys_reg(vcpu, r->reg);
> - }
>
> trace_trap_reg(__func__, r->reg, p->is_write, p->regval);
>
> @@ -1354,6 +1363,19 @@ static bool access_ccsidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> .set_user = set_raz_id_reg, \
> }
>
> +static bool access_sp_el1(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 (p->is_write)
> + vcpu->arch.ctxt.gp_regs.sp_el1 = p->regval;
> + else
> + p->regval = vcpu->arch.ctxt.gp_regs.sp_el1;
> +
> + return true;
> +}
> +
> /*
> * Architected system registers.
> * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
> @@ -1646,9 +1668,51 @@ static const struct sys_reg_desc sys_reg_descs[] = {
> */
> { SYS_DESC(SYS_PMCCFILTR_EL0), access_pmu_evtyper, reset_val, PMCCFILTR_EL0, 0 },
I have to admit I haven't gone through all the patches, or maybe this is part of
the bits that will be added at a later date, but some of the reset values seem
incorrect according to ARM DDI 0487D.a. I'll comment below the relevant registers.
>
> + { SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_val, VPIDR_EL2, 0 },
> + { SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_val, VMPIDR_EL2, 0 },
> +
> + { SYS_DESC(SYS_SCTLR_EL2), access_rw, reset_val, SCTLR_EL2, 0 },
Some bits are RES1 for SCTLR_EL2.
> + { SYS_DESC(SYS_ACTLR_EL2), access_rw, reset_val, ACTLR_EL2, 0 },
> + { SYS_DESC(SYS_HCR_EL2), access_rw, reset_val, HCR_EL2, 0 },
> + { SYS_DESC(SYS_MDCR_EL2), access_rw, reset_val, MDCR_EL2, 0 },
> + { SYS_DESC(SYS_CPTR_EL2), access_rw, reset_val, CPTR_EL2, 0 },
Some bits are RES1 for CPTR_EL2 if HCR_EL2.E2H == 0, which the reset value for
HCR_EL2 seems to imply.
> + { SYS_DESC(SYS_HSTR_EL2), access_rw, reset_val, HSTR_EL2, 0 },
> + { SYS_DESC(SYS_HACR_EL2), access_rw, reset_val, HACR_EL2, 0 },
> +
> + { SYS_DESC(SYS_TTBR0_EL2), access_rw, reset_val, TTBR0_EL2, 0 },
> + { SYS_DESC(SYS_TTBR1_EL2), access_rw, reset_val, TTBR1_EL2, 0 },
> + { SYS_DESC(SYS_TCR_EL2), access_rw, reset_val, TCR_EL2, 0 },
Same here, bits 31 and 23 are RES1 for TCR_EL2 when HCR_EL2.E2H == 0.
> + { SYS_DESC(SYS_VTTBR_EL2), access_rw, reset_val, VTTBR_EL2, 0 },
> + { SYS_DESC(SYS_VTCR_EL2), access_rw, reset_val, VTCR_EL2, 0 },
> +
> { SYS_DESC(SYS_DACR32_EL2), NULL, reset_unknown, DACR32_EL2 },
> + { SYS_DESC(SYS_SPSR_EL2), access_rw, reset_val, SPSR_EL2, 0 },
> + { SYS_DESC(SYS_ELR_EL2), access_rw, reset_val, ELR_EL2, 0 },
> + { SYS_DESC(SYS_SP_EL1), access_sp_el1},
> +
> { SYS_DESC(SYS_IFSR32_EL2), NULL, reset_unknown, IFSR32_EL2 },
> + { SYS_DESC(SYS_AFSR0_EL2), access_rw, reset_val, AFSR0_EL2, 0 },
> + { SYS_DESC(SYS_AFSR1_EL2), access_rw, reset_val, AFSR1_EL2, 0 },
> + { SYS_DESC(SYS_ESR_EL2), access_rw, reset_val, ESR_EL2, 0 },
> { SYS_DESC(SYS_FPEXC32_EL2), NULL, reset_val, FPEXC32_EL2, 0x700 },
> +
> + { SYS_DESC(SYS_FAR_EL2), access_rw, reset_val, FAR_EL2, 0 },
> + { SYS_DESC(SYS_HPFAR_EL2), access_rw, reset_val, HPFAR_EL2, 0 },
> +
> + { SYS_DESC(SYS_MAIR_EL2), access_rw, reset_val, MAIR_EL2, 0 },
> + { SYS_DESC(SYS_AMAIR_EL2), access_rw, reset_val, AMAIR_EL2, 0 },
> +
> + { SYS_DESC(SYS_VBAR_EL2), access_rw, reset_val, VBAR_EL2, 0 },
> + { SYS_DESC(SYS_RVBAR_EL2), access_rw, reset_val, RVBAR_EL2, 0 },
> + { SYS_DESC(SYS_RMR_EL2), access_rw, reset_val, RMR_EL2, 0 },
Bit AA64 [0] for RMR_EL2 is RAO/WI for EL2 cannot aarch32, which is what the
patches seem to enforce.
> +
> + { SYS_DESC(SYS_CONTEXTIDR_EL2), access_rw, reset_val, CONTEXTIDR_EL2, 0 },
> + { SYS_DESC(SYS_TPIDR_EL2), access_rw, reset_val, TPIDR_EL2, 0 },
> +
> + { SYS_DESC(SYS_CNTVOFF_EL2), access_rw, reset_val, CNTVOFF_EL2, 0 },
> + { SYS_DESC(SYS_CNTHCTL_EL2), access_rw, reset_val, CNTHCTL_EL2, 0 },
> +
> + { SYS_DESC(SYS_SP_EL2), NULL, reset_unknown, SP_EL2 },
> };
>
> static bool trap_dbgidr(struct kvm_vcpu *vcpu,