Re: [PATCH kernel v2 1/6] KVM: PPC: Rework H_PUT_TCE/H_GET_TCE handlers
From: David Gibson <hidden>
Date: 2016-01-22 01:26:36
Also in:
kvm
On Thu, Jan 21, 2016 at 06:39:32PM +1100, Alexey Kardashevskiy wrote:
This reworks the existing H_PUT_TCE/H_GET_TCE handlers to have following patches applied nicer. This moves the ioba boundaries check to a helper and adds a check for least bits which have to be zeros. The patch is pretty mechanical (only check for least ioba bits is added) so no change in behaviour is expected. Signed-off-by: Alexey Kardashevskiy <redacted>
Concept looks good, but there are a couple of nits.
quoted hunk ↗ jump to hunk
--- Changelog: v2: * compare @ret with H_SUCCESS instead of assuming H_SUCCESS is zero * made error reporting cleaner --- arch/powerpc/kvm/book3s_64_vio_hv.c | 111 +++++++++++++++++++++++------------- 1 file changed, 72 insertions(+), 39 deletions(-)diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c index 89e96b3..862f9a2 100644 --- a/arch/powerpc/kvm/book3s_64_vio_hv.c +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c@@ -35,71 +35,104 @@ #include <asm/ppc-opcode.h> #include <asm/kvm_host.h> #include <asm/udbg.h> +#include <asm/iommu.h> #define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64)) +/* + * Finds a TCE table descriptor by LIOBN. + * + * WARNING: This will be called in real or virtual mode on HV KVM and virtual + * mode on PR KVM + */ +static struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm_vcpu *vcpu, + unsigned long liobn) +{ + struct kvm *kvm = vcpu->kvm; + struct kvmppc_spapr_tce_table *stt; + + list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
list_for_each_entry_lockless? According to the comments in the header, that's for RCU protected lists, whereas this one is just protected by the lock in the kvm structure. This is replacing a plain list_for_each_entry().
+ if (stt->liobn == liobn)
+ return stt;
+
+ return NULL;
+}
+
+/*
+ * Validates IO address.
+ *
+ * WARNING: This will be called in real-mode on HV KVM and virtual
+ * mode on PR KVM
+ */
+static long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
+ unsigned long ioba, unsigned long npages)
+{
+ unsigned long mask = (1ULL << IOMMU_PAGE_SHIFT_4K) - 1;
+ unsigned long idx = ioba >> IOMMU_PAGE_SHIFT_4K;
+ unsigned long size = stt->window_size >> IOMMU_PAGE_SHIFT_4K;
+
+ if ((ioba & mask) || (idx + npages > size))It doesn't matter for the current callers, but you should check for overflow in idx + npages as well. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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