Re: [PATCH kernel] KVM: PPC: Remove redundand permission bits removal
From: David Gibson <hidden>
Date: 2018-09-10 04:50:23
On Thu, Sep 06, 2018 at 07:51:46PM +1000, Alexey Kardashevskiy wrote:
The kvmppc_gpa_to_ua() helper itself takes care of the permission bits in the TCE and yet every single caller removes them. This changes semantics of kvmppc_gpa_to_ua() so it takes TCEs (which are GPAs + TCE permission bits) to make the callers simpler. This should cause no behavioural change. Signed-off-by: Alexey Kardashevskiy <redacted>
Hmm. I like shrinking the code, but it bothers me that a function called simply kvmppc_gpa_to_ua() knows something about a TCE's internal format. I think either the TCE bit masking needs to happen in the callers, or that function needs a name change. Maybe kvmppc_tce_to_ua()?
quoted hunk ↗ jump to hunk
--- This is not related to any bug, just noticed this while doing other things. I can also rename kvmppc_gpa_to_ua() if it makes more sense, does not it? --- arch/powerpc/kvm/book3s_64_vio.c | 10 +++------- arch/powerpc/kvm/book3s_64_vio_hv.c | 16 ++++++---------- 2 files changed, 9 insertions(+), 17 deletions(-)diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 174299d..7207481 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c@@ -378,8 +378,7 @@ static long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, if (iommu_tce_check_gpa(stt->page_shift, gpa)) return H_TOO_HARD; - if (kvmppc_gpa_to_ua(stt->kvm, tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) + if (kvmppc_gpa_to_ua(stt->kvm, tce, &ua, NULL)) return H_TOO_HARD; list_for_each_entry_rcu(stit, &stt->iommu_tables, next) {@@ -553,8 +552,7 @@ long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, idx = srcu_read_lock(&vcpu->kvm->srcu); - if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, - tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL)) { + if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, tce, &ua, NULL)) { ret = H_PARAMETER; goto unlock_exit; }@@ -647,9 +645,7 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu, } tce = be64_to_cpu(tce); - if (kvmppc_gpa_to_ua(vcpu->kvm, - tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) + if (kvmppc_gpa_to_ua(vcpu->kvm, tce, &ua, NULL)) return H_PARAMETER; list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c index 5f810dc..a03cd93 100644 --- a/arch/powerpc/kvm/book3s_64_vio_hv.c +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c@@ -110,8 +110,7 @@ static long kvmppc_rm_tce_validate(struct kvmppc_spapr_tce_table *stt, if (iommu_tce_check_gpa(stt->page_shift, gpa)) return H_PARAMETER; - if (kvmppc_gpa_to_ua(stt->kvm, tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) + if (kvmppc_gpa_to_ua(stt->kvm, tce, &ua, NULL)) return H_TOO_HARD; list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {@@ -180,10 +179,10 @@ void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt, } EXPORT_SYMBOL_GPL(kvmppc_tce_put); -long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa, +long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long tce, unsigned long *ua, unsigned long **prmap) { - unsigned long gfn = gpa >> PAGE_SHIFT; + unsigned long gfn = tce >> PAGE_SHIFT; struct kvm_memory_slot *memslot; memslot = search_memslots(kvm_memslots(kvm), gfn);@@ -191,7 +190,7 @@ long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa, return -EINVAL; *ua = __gfn_to_hva_memslot(memslot, gfn) | - (gpa & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE)); + (tce & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE)); #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE if (prmap)@@ -366,8 +365,7 @@ long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn, return ret; dir = iommu_tce_direction(tce); - if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, - tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), &ua, NULL)) + if ((dir != DMA_NONE) && kvmppc_gpa_to_ua(vcpu->kvm, tce, &ua, NULL)) return H_PARAMETER; entry = ioba >> stt->page_shift;@@ -520,9 +518,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, unsigned long tce = be64_to_cpu(((u64 *)tces)[i]); ua = 0; - if (kvmppc_gpa_to_ua(vcpu->kvm, - tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) + if (kvmppc_gpa_to_ua(vcpu->kvm, tce, &ua, NULL)) return H_PARAMETER; list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
-- 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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