On Wed, 2020-09-23 at 00:10 +0300, Maxim Levitsky wrote: > This will allow the KVM to report such errors (e.g -ENOMEM) > to the userspace. > > Signed-off-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx> Reverting this and its dependency: 72f211ecaa80 KVM: x86: allow kvm_x86_ops.set_efer to return an error value on the top of linux-next (they have also unfortunately merged into the mainline at the same time) fixed an issue that a simple Intel KVM guest is unable to boot below. .config: http://people.redhat.com/qcai/x86.config qemu-kvm-4.2.0-34.module+el8.3.0+7976+077be4ec.x86_64 # /usr/libexec/qemu-kvm -name ubuntu-20.04-server-cloudimg -cpu host -smp 2 -m 2g -hda ./ubuntu-20.04-server-cloudimg.qcow2 -cdrom ./ubuntu-20.04-server-cloudimg.iso -nic user,hostfwd=tcp::2222-:22 -nographic [ 1.141022] evm: Initialising EVM extended attributes: [ 1.143344] evm: security.selinux [ 1.144968] evm: security.SMACK64 [ 1.146574] evm: security.SMACK64EXEC [ 1.148305] evm: security.SMACK64TRANSMUTE [ 1.150215] evm: security.SMACK64MMAP [ 1.151960] evm: security.apparmor [ 1.153755] evm: security.ima [ 1.155454] evm: security.capability [ 1.155456] evm: HMAC attrs: 0x1 [ 1.162331] ata1.00: ATA-7: QEMU HARDDISK, 2.5+, max UDMA/100 [ 1.162635] PM: Magic number: 8:937:635 [ 1.165607] ata1.00: 2147483648 sectors, multi 16: LBA48 [ 1.169799] scsi 0:0:0:0: Direct-Access ATA QEMU HARDDISK 2.5+ PQ: 0 ANSI: 5 [ 1.174196] rtc_cmos 00:00: setting system clock to 2020-10-26T13:38:53 UTC (1603719533) [ 1.178237] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 1.178293] sd 0:0:0:0: [sda] 2147483648 512-byte logical blocks: (1.10 TB/1.00 TiB) [ 1.180567] ata2.00: ATAPI: QEMU DVD-ROM, 2.5+, max UDMA/100 [ 1.183986] sd 0:0:0:0: [sda] Write Protect is off [error: kvm run failed No such file or directory RAX=0000000000000000 RBX=0000000000000000 RCX=0000000000000150 RDX=000000008000001c RSI=0000000000000000 RDI=0000000000000150 RBP=ffffb67840083e40 RSP=ffffb67840083e00 R8 =ffff931dfda17608 R9 =0000000000000000 R10=ffff931dfda17848 R11=0000000000000000 R12=0000000000000000 R13=00000000000000b7 R14=ffff931dfd4013c0 R15=ffffffffaa8f48d0 RIP=ffffffffaa078894 RFL=00000246 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0 ES =0000 0000000000000000 ffffffff 00c00000 CS =0010 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA] SS =0000 0000000000000000 ffffffff 00c00000 DS =0000 0000000000000000 ffffffff 00c00000 FS =0000 0000000000000000 ffffffff 00c00000 GS =0000 ffff931dfda00000 ffffffff 00c00000 LDT=0000 0000000000000000 ffffffff 00c00000 TR =0040 fffffe0000003000 0000206f 00008b00 DPL=0 TSS64-busy GDT= fffffe0000001000 0000007f IDT= fffffe0000000000 00000fff CR0=80050033 CR2=0000000000000000 CR3=000000002960a001 CR4=00760ef0 DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 DR6=00000000fffe0ff0 DR7=0000000000000400 EFER=0000000000000d01 Code=dc 60 4e 00 4c 89 e0 41 5c 5d c3 0f 1f 44 00 00 89 f0 89 f9 <0f> 30 31 c0 0f 1f 44 00 00 c3 55 48 c1 e2 20 89 f6 48 09 d6 89 c2 48 89 e5 48 83 ec 08 89 > --- > arch/x86/kvm/emulate.c | 7 +++++-- > arch/x86/kvm/x86.c | 6 +++++- > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 1d450d7710d63..d855304f5a509 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -3702,13 +3702,16 @@ static int em_dr_write(struct x86_emulate_ctxt *ctxt) > static int em_wrmsr(struct x86_emulate_ctxt *ctxt) > { > u64 msr_data; > + int ret; > > msr_data = (u32)reg_read(ctxt, VCPU_REGS_RAX) > | ((u64)reg_read(ctxt, VCPU_REGS_RDX) << 32); > - if (ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data)) > + > + ret = ctxt->ops->set_msr(ctxt, reg_read(ctxt, VCPU_REGS_RCX), msr_data); > + if (ret > 0) > return emulate_gp(ctxt, 0); > > - return X86EMUL_CONTINUE; > + return ret < 0 ? X86EMUL_UNHANDLEABLE : X86EMUL_CONTINUE; > } > > static int em_rdmsr(struct x86_emulate_ctxt *ctxt) > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 063d70e736f7f..e4b07be450d4e 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1612,8 +1612,12 @@ int kvm_emulate_wrmsr(struct kvm_vcpu *vcpu) > { > u32 ecx = kvm_rcx_read(vcpu); > u64 data = kvm_read_edx_eax(vcpu); > + int ret = kvm_set_msr(vcpu, ecx, data); > > - if (kvm_set_msr(vcpu, ecx, data)) { > + if (ret < 0) > + return ret; > + > + if (ret > 0) { > trace_kvm_msr_write_ex(ecx, data); > kvm_inject_gp(vcpu, 0); > return 1;
