The data structs for KVM_MEMORY_ENCRYPT_OP have different sizes for 32- and 64-bit
kernels, but they do not make any attempt to convert from one ABI to the other.
Fix this by adding the appropriate padding.

No functional change intended for 64-bit userspace.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20240209183743.22030-2-pbonzini@redhat.com>
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/include/uapi/asm/kvm.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 0ad6bda1fc39..b305daff056e 100644
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -687,6 +687,7 @@ enum sev_cmd_id {
 
 struct kvm_sev_cmd {
 	__u32 id;
+	__u32 pad0;
 	__u64 data;
 	__u32 error;
 	__u32 sev_fd;
@@ -697,28 +698,35 @@ struct kvm_sev_launch_start {
 	__u32 policy;
 	__u64 dh_uaddr;
 	__u32 dh_len;
+	__u32 pad0;
 	__u64 session_uaddr;
 	__u32 session_len;
+	__u32 pad1;
 };
 
 struct kvm_sev_launch_update_data {
 	__u64 uaddr;
 	__u32 len;
+	__u32 pad0;
 };
 
 
 struct kvm_sev_launch_secret {
 	__u64 hdr_uaddr;
 	__u32 hdr_len;
+	__u32 pad0;
 	__u64 guest_uaddr;
 	__u32 guest_len;
+	__u32 pad1;
 	__u64 trans_uaddr;
 	__u32 trans_len;
+	__u32 pad2;
 };
 
 struct kvm_sev_launch_measure {
 	__u64 uaddr;
 	__u32 len;
+	__u32 pad0;
 };
 
 struct kvm_sev_guest_status {
@@ -731,33 +739,43 @@ struct kvm_sev_dbg {
 	__u64 src_uaddr;
 	__u64 dst_uaddr;
 	__u32 len;
+	__u32 pad0;
 };
 
 struct kvm_sev_attestation_report {
 	__u8 mnonce[16];
 	__u64 uaddr;
 	__u32 len;
+	__u32 pad0;
 };
 
 struct kvm_sev_send_start {
 	__u32 policy;
+	__u32 pad0;
 	__u64 pdh_cert_uaddr;
 	__u32 pdh_cert_len;
+	__u32 pad1;
 	__u64 plat_certs_uaddr;
 	__u32 plat_certs_len;
+	__u32 pad2;
 	__u64 amd_certs_uaddr;
 	__u32 amd_certs_len;
+	__u32 pad3;
 	__u64 session_uaddr;
 	__u32 session_len;
+	__u32 pad4;
 };
 
 struct kvm_sev_send_update_data {
 	__u64 hdr_uaddr;
 	__u32 hdr_len;
+	__u32 pad0;
 	__u64 guest_uaddr;
 	__u32 guest_len;
+	__u32 pad1;
 	__u64 trans_uaddr;
 	__u32 trans_len;
+	__u32 pad2;
 };
 
 struct kvm_sev_receive_start {
@@ -765,17 +783,22 @@ struct kvm_sev_receive_start {
 	__u32 policy;
 	__u64 pdh_uaddr;
 	__u32 pdh_len;
+	__u32 pad0;
 	__u64 session_uaddr;
 	__u32 session_len;
+	__u32 pad1;
 };
 
 struct kvm_sev_receive_update_data {
 	__u64 hdr_uaddr;
 	__u32 hdr_len;
+	__u32 pad0;
 	__u64 guest_uaddr;
 	__u32 guest_len;
+	__u32 pad1;
 	__u64 trans_uaddr;
 	__u32 trans_len;
+	__u32 pad2;
 };
 
 #define KVM_X2APIC_API_USE_32BIT_IDS            (1ULL << 0)
-- 
2.39.1

On Fri, Feb 23, 2024, Paolo Bonzini wrote:
> The data structs for KVM_MEMORY_ENCRYPT_OP have different sizes for 32- and 64-bit
> kernels, but they do not make any attempt to convert from one ABI to the other.
> Fix this by adding the appropriate padding.

Maybe call out that SEV+ is 64-bit only, so this doesn't matter in practice?  Or
does this affect .compat_ioctl()?

> No functional change intended for 64-bit userspace.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Message-Id: <20240209183743.22030-2-pbonzini@redhat.com>
> Reviewed-by: Michael Roth <michael.roth@amd.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Heh, you've double-stamped several of the patches in this series.

Reviewed-by: Sean Christopherson <seanjc@google.com>

On 2/23/24 15:20, Sean Christopherson wrote:
> On Fri, Feb 23, 2024, Paolo Bonzini wrote:
>> The data structs for KVM_MEMORY_ENCRYPT_OP have different sizes for 32- and 64-bit
>> kernels, but they do not make any attempt to convert from one ABI to the other.
>> Fix this by adding the appropriate padding.
> Maybe call out that SEV+ is 64-bit only, so this doesn't matter in practice?  Or
> does this affect .compat_ioctl()?

Yes, .compat_ioctl() is what I had in mind - but that means I have to 
change "32- and 64-bit kernels" to "... userspace".

Paolo