5.15-stable review patch. If anyone has any objections, please let me know.
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From: Sean Christopherson seanjc@google.com
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@vger.kernel.org Cc: Tom Lendacky thomas.lendacky@amd.com Reviewed-by: Xiaoyao Li xiaoyao.li@intel.com Reviewed-by: Nikunj A Dadhania nikunj@amd.com Reviewed-by: Tom Lendacky thomas.lendacky@amd.com Reviewed-by: Binbin Wu binbin.wu@linux.intel.com Reviewed-by: Kai Huang kai.huang@intel.com Link: https://lore.kernel.org/r/20241128004344.4072099-2-seanjc@google.com Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -8946,7 +8946,7 @@ 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;