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

Suzuki K Poulose
2019-07-01T16:36:11Z

Hi Marc,

On 21/06/2019 10:37, 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 */

Does it need to include the following registers Counter-timer Hyp Physical timer
registers ? i.e, CNTHP_{CTL,CVAL,TVAL}_EL2. Or do we have some other magic with
NV for the virtual EL2 ?

Cheers
Suzuki