Messages in this thread |  | | Date | Tue, 23 Feb 2021 17:56:40 +0800 | From | Aili Yao <> | Subject | Re: [PATCH v2] x86/mce: fix wrong no-return-ip logic in do_machine_check() |
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On Tue, 23 Feb 2021 10:43:00 +0100 Borislav Petkov <bp@alien8.de> wrote:
> On Tue, Feb 23, 2021 at 10:27:55AM +0800, Aili Yao wrote: > > When Guest access one address with UE error, it will exit guest mode, > > the host will do the recovery job, and then one SIGBUS is send to > > the VCPU and qemu will catch the signal, there is only address and > > error level no RIPV in signal, so qemu will assume RIPV is cleared and > > inject the error into guest OS. > > Lemme see: > > void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr) > > /* If we get an action required MCE, it has been injected by KVM > * while the VM was running. An action optional MCE instead should > * be coming from the main thread, which qemu_init_sigbus identifies > * as the "early kill" thread. > */ > assert(code == BUS_MCEERR_AR || code == BUS_MCEERR_AO); > > ... > > kvm_mce_inject(cpu, paddr, code); > > in that function: > > if (code == BUS_MCEERR_AR) { > status |= MCI_STATUS_AR | 0x134; > mcg_status |= MCG_STATUS_EIPV; > } else { > status |= 0xc0; > mcg_status |= MCG_STATUS_RIPV; > } > > That looks like a valid RIP bit to me. Then cpu_x86_inject_mce() gets > that mcg_status and injects it into the guest.
What i inject is AR error, and I don't see MCG_STATUS_RIPV flag.
Tks Aili Yao
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