On 29/06/2019 06:08, Claudio Carvalho wrote:
> When the ultravisor firmware is available, it takes control over the
> LDBAR register. In this case, thread-imc updates and save/restore
> operations on the LDBAR register are handled by ultravisor.
What does LDBAR do? "Power ISA™ Version 3.0 B" or "User’s Manual POWER9
Processor" do not tell.
>
> Signed-off-by: Claudio Carvalho <cclaudio@xxxxxxxxxxxxx>
> Reviewed-by: Ram Pai <linuxram@xxxxxxxxxx>
> Reviewed-by: Ryan Grimm <grimm@xxxxxxxxxxxxx>
> Acked-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
> Acked-by: Paul Mackerras <paulus@xxxxxxxxxx>
> ---
> arch/powerpc/kvm/book3s_hv_rmhandlers.S | 2 ++
> arch/powerpc/platforms/powernv/idle.c | 6 ++++--
> arch/powerpc/platforms/powernv/opal-imc.c | 4 ++++
> 3 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> index f9b2620fbecd..cffb365d9d02 100644
> --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
> @@ -375,8 +375,10 @@ BEGIN_FTR_SECTION
> mtspr SPRN_RPR, r0
> ld r0, KVM_SPLIT_PMMAR(r6)
> mtspr SPRN_PMMAR, r0
> +BEGIN_FW_FTR_SECTION_NESTED(70)
> ld r0, KVM_SPLIT_LDBAR(r6)
> mtspr SPRN_LDBAR, r0
> +END_FW_FTR_SECTION_NESTED(FW_FEATURE_ULTRAVISOR, 0, 70)
> isync
> FTR_SECTION_ELSE
> /* On P9 we use the split_info for coordinating LPCR changes */
> diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> index 77f2e0a4ee37..5593a2d55959 100644
> --- a/arch/powerpc/platforms/powernv/idle.c
> +++ b/arch/powerpc/platforms/powernv/idle.c
> @@ -679,7 +679,8 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
> sprs.ptcr = mfspr(SPRN_PTCR);
> sprs.rpr = mfspr(SPRN_RPR);
> sprs.tscr = mfspr(SPRN_TSCR);
> - sprs.ldbar = mfspr(SPRN_LDBAR);
> + if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
> + sprs.ldbar = mfspr(SPRN_LDBAR);
>
> sprs_saved = true;
>
> @@ -762,7 +763,8 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
> mtspr(SPRN_PTCR, sprs.ptcr);
> mtspr(SPRN_RPR, sprs.rpr);
> mtspr(SPRN_TSCR, sprs.tscr);
> - mtspr(SPRN_LDBAR, sprs.ldbar);
> + if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
> + mtspr(SPRN_LDBAR, sprs.ldbar);
>
> if (pls >= pnv_first_tb_loss_level) {
> /* TB loss */
> diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/powerpc/platforms/powernv/opal-imc.c
> index 1b6932890a73..5fe2d4526cbc 100644
> --- a/arch/powerpc/platforms/powernv/opal-imc.c
> +++ b/arch/powerpc/platforms/powernv/opal-imc.c
> @@ -254,6 +254,10 @@ static int opal_imc_counters_probe(struct platform_device *pdev)
> bool core_imc_reg = false, thread_imc_reg = false;
> u32 type;
>
> + /* Disable IMC devices, when Ultravisor is enabled. */
> + if (firmware_has_feature(FW_FEATURE_ULTRAVISOR))
> + return -EACCES;
> +
> /*
> * Check whether this is kdump kernel. If yes, force the engines to
> * stop and return.
>
--
Alexey
