On Thu, Jan 21, 2016 at 06:39:37PM +1100, Alexey Kardashevskiy wrote:
> This adds real and virtual mode handlers for the H_PUT_TCE_INDIRECT and
> H_STUFF_TCE hypercalls for user space emulated devices such as IBMVIO
> devices or emulated PCI. These calls allow adding multiple entries
> (up to 512) into the TCE table in one call which saves time on
> transition between kernel and user space.
>
> This implements the KVM_CAP_PPC_MULTITCE capability. When present,
> the kernel will try handling H_PUT_TCE_INDIRECT and H_STUFF_TCE.
> If they can not be handled by the kernel, they are passed on to
> the user space. The user space still has to have an implementation
> for these.
>
> Both HV and PR-syle KVM are supported.
>
> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
[snip]
> diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
> index 975f0ab..987f406 100644
> --- a/arch/powerpc/kvm/book3s_64_vio.c
> +++ b/arch/powerpc/kvm/book3s_64_vio.c
> @@ -14,6 +14,7 @@
> *
> * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@xxxxxxxxxxx>
> * Copyright 2011 David Gibson, IBM Corporation <dwg@xxxxxxxxxxx>
> + * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@xxxxxxxxxxx>
> */
>
> #include <linux/types.h>
> @@ -37,8 +38,7 @@
> #include <asm/kvm_host.h>
> #include <asm/udbg.h>
> #include <asm/iommu.h>
> -
> -#define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64))
> +#include <asm/tce.h>
>
> static unsigned long kvmppc_stt_npages(unsigned long window_size)
> {
> @@ -200,3 +200,109 @@ fail:
> }
> return ret;
> }
> +
> +long kvmppc_h_put_tce(struct kvm_vcpu *vcpu,
> + unsigned long liobn, unsigned long ioba,
> + unsigned long tce)
> +{
> + long ret;
> + struct kvmppc_spapr_tce_table *stt;
> +
> + stt = kvmppc_find_table(vcpu, liobn);
> + if (!stt)
> + return H_TOO_HARD;
> +
> + ret = kvmppc_ioba_validate(stt, ioba, 1);
> + if (ret != H_SUCCESS)
> + return ret;
> +
> + ret = kvmppc_tce_validate(stt, tce);
> + if (ret != H_SUCCESS)
> + return ret;
> +
> + kvmppc_tce_put(stt, ioba >> IOMMU_PAGE_SHIFT_4K, tce);
> +
> + return H_SUCCESS;
> +}
> +EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
As far as I can see, this is functionally identical to the
kvmppc_h_put_tce that we have in book3s_64_vio_hv.c, that gets renamed
later on in this patch. It would be good to have an explanation in
the commit message why we want two almost-identical functions (and
similarly for kvmppc_h_stuff_tce). Is it because a future patch is
going to make them different, for instance?
> +long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
> + unsigned long liobn, unsigned long ioba,
> + unsigned long tce_value, unsigned long npages)
> +{
> + struct kvmppc_spapr_tce_table *stt;
> + long i, ret;
> +
> + stt = kvmppc_find_table(vcpu, liobn);
> + if (!stt)
> + return H_TOO_HARD;
> +
> + ret = kvmppc_ioba_validate(stt, ioba, npages);
> + if (ret != H_SUCCESS)
> + return ret;
> +
> + if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
> + return H_PARAMETER;
> +
> + for (i = 0; i < npages; ++i, ioba += IOMMU_PAGE_SIZE_4K)
Looks like we need a bounds check on npages, presumably in
kvmppc_ioba_validate().
> diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
> index 8cd3a95..58c63ed 100644
> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
[...]
> +long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
> + unsigned long liobn, unsigned long ioba,
> + unsigned long tce_list, unsigned long npages)
> +{
> + struct kvmppc_spapr_tce_table *stt;
> + long i, ret = H_SUCCESS;
> + unsigned long tces, entry, ua = 0;
> + unsigned long *rmap = NULL;
> +
> + stt = kvmppc_find_table(vcpu, liobn);
> + if (!stt)
> + return H_TOO_HARD;
> +
> + entry = ioba >> IOMMU_PAGE_SHIFT_4K;
> + /*
> + * The spec says that the maximum size of the list is 512 TCEs
> + * so the whole table addressed resides in 4K page
> + */
> + if (npages > 512)
> + return H_PARAMETER;
> +
> + if (tce_list & (SZ_4K - 1))
> + return H_PARAMETER;
> +
> + ret = kvmppc_ioba_validate(stt, ioba, npages);
> + if (ret != H_SUCCESS)
> + return ret;
> +
> + if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, &rmap))
> + return H_TOO_HARD;
> +
> + rmap = (void *) vmalloc_to_phys(rmap);
> +
> + lock_rmap(rmap);
A comment here explaining why we lock the rmap and what that achieves
would be useful for future generations.
> + if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) {
> + ret = H_TOO_HARD;
> + goto unlock_exit;
> + }
> +
> + for (i = 0; i < npages; ++i) {
> + unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
> +
> + ret = kvmppc_tce_validate(stt, tce);
> + if (ret != H_SUCCESS)
> + goto unlock_exit;
> +
> + kvmppc_tce_put(stt, entry + i, tce);
> + }
> +
> +unlock_exit:
> + unlock_rmap(rmap);
> +
> + return ret;
> +}
Paul.
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