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KVM: PPC: Explicitly require struct page memory for Ultravisor sharing

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Explicitly require "struct page" memory when sharing memory between
guest and host via an Ultravisor.  Given the number of pfn_to_page()
calls in the code, it's safe to assume that KVM already requires that the
pfn returned by gfn_to_pfn() is backed by struct page, i.e. this is
likely a bug fix, not a reduction in KVM capabilities.

Switching to gfn_to_page() will eventually allow removing gfn_to_pfn()
and kvm_pfn_to_refcounted_page().

Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-79-seanjc@google.com>
This commit is contained in:
Sean Christopherson 2024-10-10 11:24:20 -07:00 committed by Paolo Bonzini
parent 570d666c11
commit 040537ce87
1 changed files with 12 additions and 13 deletions
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25
arch/powerpc/kvm/book3s_hv_uvmem.c
View File

@ -879,9 +879,8 @@ static unsigned long kvmppc_share_page(struct kvm *kvm, unsigned long gpa,
{ {
int ret = H_PARAMETER; int ret = H_PARAMETER;
struct page *uvmem_page; struct page *page, *uvmem_page;
struct kvmppc_uvmem_page_pvt *pvt; struct kvmppc_uvmem_page_pvt *pvt;
unsigned long pfn;
unsigned long gfn = gpa >> page_shift; unsigned long gfn = gpa >> page_shift;
int srcu_idx; int srcu_idx;
unsigned long uvmem_pfn; unsigned long uvmem_pfn;
@ -901,8 +900,8 @@ static unsigned long kvmppc_share_page(struct kvm *kvm, unsigned long gpa,
retry: retry:
mutex_unlock(&kvm->arch.uvmem_lock); mutex_unlock(&kvm->arch.uvmem_lock);
pfn = gfn_to_pfn(kvm, gfn); page = gfn_to_page(kvm, gfn);
if (is_error_noslot_pfn(pfn)) if (!page)
goto out; goto out;
mutex_lock(&kvm->arch.uvmem_lock); mutex_lock(&kvm->arch.uvmem_lock);
@ -911,16 +910,16 @@ retry:
pvt = uvmem_page->zone_device_data; pvt = uvmem_page->zone_device_data;
pvt->skip_page_out = true; pvt->skip_page_out = true;
pvt->remove_gfn = false; /* it continues to be a valid GFN */ pvt->remove_gfn = false; /* it continues to be a valid GFN */
kvm_release_pfn_clean(pfn); kvm_release_page_unused(page);
goto retry; goto retry;
} }
if (!uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, if (!uv_page_in(kvm->arch.lpid, page_to_pfn(page) << page_shift, gpa, 0,
page_shift)) { page_shift)) {
kvmppc_gfn_shared(gfn, kvm); kvmppc_gfn_shared(gfn, kvm);
ret = H_SUCCESS; ret = H_SUCCESS;
} }
kvm_release_pfn_clean(pfn); kvm_release_page_clean(page);
mutex_unlock(&kvm->arch.uvmem_lock); mutex_unlock(&kvm->arch.uvmem_lock);
out: out:
srcu_read_unlock(&kvm->srcu, srcu_idx); srcu_read_unlock(&kvm->srcu, srcu_idx);
@ -1083,21 +1082,21 @@ out:
int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn) int kvmppc_send_page_to_uv(struct kvm *kvm, unsigned long gfn)
{ {
unsigned long pfn; struct page *page;
int ret = U_SUCCESS; int ret = U_SUCCESS;
pfn = gfn_to_pfn(kvm, gfn); page = gfn_to_page(kvm, gfn);
if (is_error_noslot_pfn(pfn)) if (!page)
return -EFAULT; return -EFAULT;
mutex_lock(&kvm->arch.uvmem_lock); mutex_lock(&kvm->arch.uvmem_lock);
if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL)) if (kvmppc_gfn_is_uvmem_pfn(gfn, kvm, NULL))
goto out; goto out;
ret = uv_page_in(kvm->arch.lpid, pfn << PAGE_SHIFT, gfn << PAGE_SHIFT, ret = uv_page_in(kvm->arch.lpid, page_to_pfn(page) << PAGE_SHIFT,
0, PAGE_SHIFT); gfn << PAGE_SHIFT, 0, PAGE_SHIFT);
out: out:
kvm_release_pfn_clean(pfn); kvm_release_page_clean(page);
mutex_unlock(&kvm->arch.uvmem_lock); mutex_unlock(&kvm->arch.uvmem_lock);
return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT; return (ret == U_SUCCESS) ? RESUME_GUEST : -EFAULT;
} }