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author | Ravi Bangoria <ravi.bangoria@linux.ibm.com> | 2020-12-16 13:42:16 +0300 |
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committer | Paul Mackerras <paulus@ozlabs.org> | 2021-02-10 06:31:08 +0300 |
commit | afe75049303f75c73a97d635a4d353c7d571d1a3 (patch) | |
tree | 998919096486724bdfe051fccd955e262cf0282f /arch/powerpc/kvm/book3s_hv_nested.c | |
parent | 9294b8a12585f8b4ccb9c060b54bab0bd13f24b9 (diff) | |
download | linux-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.c | 55 |
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; |