Re: [PATCH v5 33/37] KVM: arm64: Add POE save/restore for AT emulation fast-path

Joey Gouly
2024-10-24T15:26:21Z

On Wed, Oct 23, 2024 at 03:53:41PM +0100, Marc Zyngier wrote:
> Just like the other extensions affecting address translation,
> we must save/restore POE so that an out-of-context translation
> context can be restored and used with the AT instructions.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Joey Gouly <joey.gouly@arm.com>

> ---
> arch/arm64/kvm/at.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/arch/arm64/kvm/at.c b/arch/arm64/kvm/at.c
> index de7109111e404..ef1643faedeb4 100644
> --- a/arch/arm64/kvm/at.c
> +++ b/arch/arm64/kvm/at.c
> @@ -440,6 +440,8 @@ struct mmu_config {
> u64 tcr2;
> u64 pir;
> u64 pire0;
> + u64 por_el0;
> + u64 por_el1;
> u64 sctlr;
> u64 vttbr;
> u64 vtcr;
> @@ -458,6 +460,10 @@ static void __mmu_config_save(struct mmu_config *config)
> config->pir = read_sysreg_el1(SYS_PIR);
> config->pire0 = read_sysreg_el1(SYS_PIRE0);
> }
> + if (system_supports_poe()) {
> + config->por_el1 = read_sysreg_el1(SYS_POR);
> + config->por_el0 = read_sysreg_s(SYS_POR_EL0);
> + }
> }
> config->sctlr = read_sysreg_el1(SYS_SCTLR);
> config->vttbr = read_sysreg(vttbr_el2);
> @@ -485,6 +491,10 @@ static void __mmu_config_restore(struct mmu_config *config)
> write_sysreg_el1(config->pir, SYS_PIR);
> write_sysreg_el1(config->pire0, SYS_PIRE0);
> }
> + if (system_supports_poe()) {
> + write_sysreg_el1(config->por_el1, SYS_POR);
> + write_sysreg_s(config->por_el0, SYS_POR_EL0);
> + }
> }
> write_sysreg_el1(config->sctlr, SYS_SCTLR);
> write_sysreg(config->vttbr, vttbr_el2);
> @@ -1105,6 +1115,10 @@ static u64 __kvm_at_s1e01_fast(struct kvm_vcpu *vcpu, u32 op, u64 vaddr)
> write_sysreg_el1(vcpu_read_sys_reg(vcpu, PIR_EL1), SYS_PIR);
> write_sysreg_el1(vcpu_read_sys_reg(vcpu, PIRE0_EL1), SYS_PIRE0);
> }
> + if (kvm_has_s1poe(vcpu->kvm)) {
> + write_sysreg_el1(vcpu_read_sys_reg(vcpu, POR_EL1), SYS_POR);
> + write_sysreg_s(vcpu_read_sys_reg(vcpu, POR_EL0), SYS_POR_EL0);
> + }
> }
> write_sysreg_el1(vcpu_read_sys_reg(vcpu, SCTLR_EL1), SYS_SCTLR);
> __load_stage2(mmu, mmu->arch);
> --
> 2.39.2
>