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authorRavi Bangoria <ravi.bangoria@linux.ibm.com>2020-12-16 13:42:16 +0300
committerPaul Mackerras <paulus@ozlabs.org>2021-02-10 06:31:08 +0300
commitafe75049303f75c73a97d635a4d353c7d571d1a3 (patch)
tree998919096486724bdfe051fccd955e262cf0282f /arch/powerpc/kvm/book3s_hv_nested.c
parent9294b8a12585f8b4ccb9c060b54bab0bd13f24b9 (diff)
downloadlinux-afe75049303f75c73a97d635a4d353c7d571d1a3.tar.xz
KVM: PPC: Book3S HV: Allow nested guest creation when L0 hv_guest_state > L1
On powerpc, L1 hypervisor takes help of L0 using H_ENTER_NESTED hcall to load L2 guest state in cpu. L1 hypervisor prepares the L2 state in struct hv_guest_state and passes a pointer to it via hcall. Using that pointer, L0 reads/writes that state directly from/to L1 memory. Thus L0 must be aware of hv_guest_state layout of L1. Currently it uses version field to achieve this. i.e. If L0 hv_guest_state.version != L1 hv_guest_state.version, L0 won't allow nested kvm guest. This restriction can be loosened up a bit. L0 can be taught to understand older layout of hv_guest_state, if we restrict the new members to be added only at the end, i.e. we can allow nested guest even when L0 hv_guest_state.version > L1 hv_guest_state.version. Though, the other way around is not possible. Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_nested.c')
-rw-r--r--arch/powerpc/kvm/book3s_hv_nested.c55
1 files changed, 45 insertions, 10 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 33b58549a9aa..5b8043cf4668 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -215,12 +215,51 @@ static void kvmhv_nested_mmio_needed(struct kvm_vcpu *vcpu, u64 regs_ptr)
}
}
+static int kvmhv_read_guest_state_and_regs(struct kvm_vcpu *vcpu,
+ struct hv_guest_state *l2_hv,
+ struct pt_regs *l2_regs,
+ u64 hv_ptr, u64 regs_ptr)
+{
+ int size;
+
+ if (kvm_vcpu_read_guest(vcpu, hv_ptr, &l2_hv->version,
+ sizeof(l2_hv->version)))
+ return -1;
+
+ if (kvmppc_need_byteswap(vcpu))
+ l2_hv->version = swab64(l2_hv->version);
+
+ size = hv_guest_state_size(l2_hv->version);
+ if (size < 0)
+ return -1;
+
+ return kvm_vcpu_read_guest(vcpu, hv_ptr, l2_hv, size) ||
+ kvm_vcpu_read_guest(vcpu, regs_ptr, l2_regs,
+ sizeof(struct pt_regs));
+}
+
+static int kvmhv_write_guest_state_and_regs(struct kvm_vcpu *vcpu,
+ struct hv_guest_state *l2_hv,
+ struct pt_regs *l2_regs,
+ u64 hv_ptr, u64 regs_ptr)
+{
+ int size;
+
+ size = hv_guest_state_size(l2_hv->version);
+ if (size < 0)
+ return -1;
+
+ return kvm_vcpu_write_guest(vcpu, hv_ptr, l2_hv, size) ||
+ kvm_vcpu_write_guest(vcpu, regs_ptr, l2_regs,
+ sizeof(struct pt_regs));
+}
+
long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
{
long int err, r;
struct kvm_nested_guest *l2;
struct pt_regs l2_regs, saved_l1_regs;
- struct hv_guest_state l2_hv, saved_l1_hv;
+ struct hv_guest_state l2_hv = {0}, saved_l1_hv;
struct kvmppc_vcore *vc = vcpu->arch.vcore;
u64 hv_ptr, regs_ptr;
u64 hdec_exp;
@@ -235,17 +274,15 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
hv_ptr = kvmppc_get_gpr(vcpu, 4);
regs_ptr = kvmppc_get_gpr(vcpu, 5);
vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
- err = kvm_vcpu_read_guest(vcpu, hv_ptr, &l2_hv,
- sizeof(struct hv_guest_state)) ||
- kvm_vcpu_read_guest(vcpu, regs_ptr, &l2_regs,
- sizeof(struct pt_regs));
+ err = kvmhv_read_guest_state_and_regs(vcpu, &l2_hv, &l2_regs,
+ hv_ptr, regs_ptr);
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
if (err)
return H_PARAMETER;
if (kvmppc_need_byteswap(vcpu))
byteswap_hv_regs(&l2_hv);
- if (l2_hv.version != HV_GUEST_STATE_VERSION)
+ if (l2_hv.version > HV_GUEST_STATE_VERSION)
return H_P2;
if (kvmppc_need_byteswap(vcpu))
@@ -325,10 +362,8 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
byteswap_pt_regs(&l2_regs);
}
vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
- err = kvm_vcpu_write_guest(vcpu, hv_ptr, &l2_hv,
- sizeof(struct hv_guest_state)) ||
- kvm_vcpu_write_guest(vcpu, regs_ptr, &l2_regs,
- sizeof(struct pt_regs));
+ err = kvmhv_write_guest_state_and_regs(vcpu, &l2_hv, &l2_regs,
+ hv_ptr, regs_ptr);
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
if (err)
return H_AUTHORITY;