On Tue, 2 Feb 2021 15:13:10 +1100
David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> wrote:
> While we've abstracted some (potential) differences between mechanisms for
> securing guest memory, the initialization is still specific to SEV. Given
> that, move it into x86's kvm_arch_init() code, rather than the generic
> kvm_init() code.
>
> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
> ---
Reviewed-by: Greg Kurz <groug@xxxxxxxx>
> accel/kvm/kvm-all.c | 14 --------------
> accel/kvm/sev-stub.c | 4 ++--
> target/i386/kvm/kvm.c | 20 ++++++++++++++++++++
> target/i386/sev.c | 7 ++++++-
> 4 files changed, 28 insertions(+), 17 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 3d820d0c7d..7150acdbcc 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2180,20 +2180,6 @@ static int kvm_init(MachineState *ms)
>
> kvm_state = s;
>
> - /*
> - * if memory encryption object is specified then initialize the memory
> - * encryption context.
> - */
> - if (ms->cgs) {
> - Error *local_err = NULL;
> - /* FIXME handle mechanisms other than SEV */
> - ret = sev_kvm_init(ms->cgs, &local_err);
> - if (ret < 0) {
> - error_report_err(local_err);
> - goto err;
> - }
> - }
> -
> ret = kvm_arch_init(ms, s);
> if (ret < 0) {
> goto err;
> diff --git a/accel/kvm/sev-stub.c b/accel/kvm/sev-stub.c
> index 512e205f7f..9587d1b2a3 100644
> --- a/accel/kvm/sev-stub.c
> +++ b/accel/kvm/sev-stub.c
> @@ -17,6 +17,6 @@
>
> int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
> {
> - /* SEV can't be selected if it's not compiled */
> - g_assert_not_reached();
> + /* If we get here, cgs must be some non-SEV thing */
> + return 0;
> }
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index 6dc1ee052d..4788139128 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -42,6 +42,7 @@
> #include "hw/i386/intel_iommu.h"
> #include "hw/i386/x86-iommu.h"
> #include "hw/i386/e820_memory_layout.h"
> +#include "sysemu/sev.h"
>
> #include "hw/pci/pci.h"
> #include "hw/pci/msi.h"
> @@ -2135,6 +2136,25 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> uint64_t shadow_mem;
> int ret;
> struct utsname utsname;
> + Error *local_err = NULL;
> +
> + /*
> + * Initialize SEV context, if required
> + *
> + * If no memory encryption is requested (ms->cgs == NULL) this is
> + * a no-op.
> + *
> + * It's also a no-op if a non-SEV confidential guest support
> + * mechanism is selected. SEV is the only mechanism available to
> + * select on x86 at present, so this doesn't arise, but if new
> + * mechanisms are supported in future (e.g. TDX), they'll need
> + * their own initialization either here or elsewhere.
> + */
> + ret = sev_kvm_init(ms->cgs, &local_err);
> + if (ret < 0) {
> + error_report_err(local_err);
> + return ret;
> + }
>
> if (!kvm_check_extension(s, KVM_CAP_IRQ_ROUTING)) {
> error_report("kvm: KVM_CAP_IRQ_ROUTING not supported by KVM");
> diff --git a/target/i386/sev.c b/target/i386/sev.c
> index f9e9b5d8ae..11c9a3cc21 100644
> --- a/target/i386/sev.c
> +++ b/target/i386/sev.c
> @@ -664,13 +664,18 @@ sev_vm_state_change(void *opaque, int running, RunState state)
>
> int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
> {
> - SevGuestState *sev = SEV_GUEST(cgs);
> + SevGuestState *sev
> + = (SevGuestState *)object_dynamic_cast(OBJECT(cgs), TYPE_SEV_GUEST);
> char *devname;
> int ret, fw_error;
> uint32_t ebx;
> uint32_t host_cbitpos;
> struct sev_user_data_status status = {};
>
> + if (!sev) {
> + return 0;
> + }
> +
> ret = ram_block_discard_disable(true);
> if (ret) {
> error_report("%s: cannot disable RAM discard", __func__);
