[PATCH 5/8] KVM: PPC: Update kvmppc_st and kvmppc_ld to use quadrants
From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Date: 2018-12-07 04:02:13
Also in:
kvm
Subsystem:
kernel virtual machine for powerpc (kvm/powerpc), linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
The functions kvmppc_st and kvmppc_ld are used to access guest memory from the host using a guest effective address. They do so by translating through the process table to obtain a guest real address and then using kvm_read_guest or kvm_write_guest to make the access with the guest real address. This method of access however only works for L1 guests and will give the incorrect results for a nested guest. We can however use the store_to_eaddr and load_from_eaddr kvmppc_ops to perform the access for a nested guesti (and a L1 guest). So attempt this method first and fall back to the old method if this fails and we aren't running a nested guest. At this stage there is no fall back method to perform the access for a nested guest and this is left as a future improvement. For now we will return to the nested guest and rely on the fact that a translation should be faulted in before retrying the access. Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com> --- arch/powerpc/kvm/powerpc.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 95859c53a5cd..cb029fcab404 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c@@ -331,10 +331,17 @@ int kvmppc_st(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr, { ulong mp_pa = vcpu->arch.magic_page_pa & KVM_PAM & PAGE_MASK; struct kvmppc_pte pte; - int r; + int r = -EINVAL; vcpu->stat.st++; + if (vcpu->kvm->arch.kvm_ops && vcpu->kvm->arch.kvm_ops->store_to_eaddr) + r = vcpu->kvm->arch.kvm_ops->store_to_eaddr(vcpu, eaddr, ptr, + size); + + if ((!r) || (r == -EAGAIN)) + return r; + r = kvmppc_xlate(vcpu, *eaddr, data ? XLATE_DATA : XLATE_INST, XLATE_WRITE, &pte); if (r < 0)
@@ -367,10 +374,17 @@ int kvmppc_ld(struct kvm_vcpu *vcpu, ulong *eaddr, int size, void *ptr, { ulong mp_pa = vcpu->arch.magic_page_pa & KVM_PAM & PAGE_MASK; struct kvmppc_pte pte; - int rc; + int rc = -EINVAL; vcpu->stat.ld++; + if (vcpu->kvm->arch.kvm_ops && vcpu->kvm->arch.kvm_ops->load_from_eaddr) + rc = vcpu->kvm->arch.kvm_ops->load_from_eaddr(vcpu, eaddr, ptr, + size); + + if ((!rc) || (rc == -EAGAIN)) + return rc; + rc = kvmppc_xlate(vcpu, *eaddr, data ? XLATE_DATA : XLATE_INST, XLATE_READ, &pte); if (rc)
--
2.13.6