6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sean Christopherson <seanjc@xxxxxxxxxx>
commit 9b42d1e8e4fe9dc631162c04caa69b0d1860b0f0 upstream.
Use is_64_bit_hypercall() instead of is_64_bit_mode() to detect a 64-bit
hypercall when completing said hypercall. For guests with protected state,
e.g. SEV-ES and SEV-SNP, KVM must assume the hypercall was made in 64-bit
mode as the vCPU state needed to detect 64-bit mode is unavailable.
Hacking the sev_smoke_test selftest to generate a KVM_HC_MAP_GPA_RANGE
hypercall via VMGEXIT trips the WARN:
------------[ cut here ]------------
WARNING: CPU: 273 PID: 326626 at arch/x86/kvm/x86.h:180 complete_hypercall_exit+0x44/0xe0 [kvm]
Modules linked in: kvm_amd kvm ... [last unloaded: kvm]
CPU: 273 UID: 0 PID: 326626 Comm: sev_smoke_test Not tainted 6.12.0-smp--392e932fa0f3-feat #470
Hardware name: Google Astoria/astoria, BIOS 0.20240617.0-0 06/17/2024
RIP: 0010:complete_hypercall_exit+0x44/0xe0 [kvm]
Call Trace:
<TASK>
kvm_arch_vcpu_ioctl_run+0x2400/0x2720 [kvm]
kvm_vcpu_ioctl+0x54f/0x630 [kvm]
__se_sys_ioctl+0x6b/0xc0
do_syscall_64+0x83/0x160
entry_SYSCALL_64_after_hwframe+0x76/0x7e
</TASK>
---[ end trace 0000000000000000 ]---
Fixes: b5aead0064f3 ("KVM: x86: Assume a 64-bit hypercall for guests with protected state")
Cc: stable@xxxxxxxxxxxxxxx
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Reviewed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
Reviewed-by: Nikunj A Dadhania <nikunj@xxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
Link: https://lore.kernel.org/r/20241128004344.4072099-2-seanjc@xxxxxxxxxx
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9991,7 +9991,7 @@ static int complete_hypercall_exit(struc
{
u64 ret = vcpu->run->hypercall.ret;
- if (!is_64_bit_mode(vcpu))
+ if (!is_64_bit_hypercall(vcpu))
ret = (u32)ret;
kvm_rax_write(vcpu, ret);
++vcpu->stat.hypercalls;
