Radim Krčmář 05d8d34611 KVM: nVMX: do not warn when MSR bitmap address is not backed ... Before trying to do nested_get_page() in nested_vmx_merge_msr_bitmap(), we have already checked that the MSR bitmap address is valid (4k aligned and within physical limits). SDM doesn't specify what happens if the there is no memory mapped at the valid address, but Intel CPUs treat the situation as if the bitmap was configured to trap all MSRs. KVM already does that by returning false and a correct handling doesn't need the guest-trigerrable warning that was reported by syzkaller: (The warning was originally there to catch some possible bugs in nVMX.) ------------[ cut here ]------------ WARNING: CPU: 0 PID: 7832 at arch/x86/kvm/vmx.c:9709 nested_vmx_merge_msr_bitmap arch/x86/kvm/vmx.c:9709 [inline] WARNING: CPU: 0 PID: 7832 at arch/x86/kvm/vmx.c:9709 nested_get_vmcs12_pages+0xfb6/0x15c0 arch/x86/kvm/vmx.c:9640 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 7832 Comm: syz-executor1 Not tainted 4.10.0+ #229 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:15 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:51 panic+0x1fb/0x412 kernel/panic.c:179 __warn+0x1c4/0x1e0 kernel/panic.c:540 warn_slowpath_null+0x2c/0x40 kernel/panic.c:583 nested_vmx_merge_msr_bitmap arch/x86/kvm/vmx.c:9709 [inline] nested_get_vmcs12_pages+0xfb6/0x15c0 arch/x86/kvm/vmx.c:9640 enter_vmx_non_root_mode arch/x86/kvm/vmx.c:10471 [inline] nested_vmx_run+0x6186/0xaab0 arch/x86/kvm/vmx.c:10561 handle_vmlaunch+0x1a/0x20 arch/x86/kvm/vmx.c:7312 vmx_handle_exit+0xfc0/0x3f00 arch/x86/kvm/vmx.c:8526 vcpu_enter_guest arch/x86/kvm/x86.c:6982 [inline] vcpu_run arch/x86/kvm/x86.c:7044 [inline] kvm_arch_vcpu_ioctl_run+0x1418/0x4840 arch/x86/kvm/x86.c:7205 kvm_vcpu_ioctl+0x673/0x1120 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2570 Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> [Jim Mattson explained the bare metal behavior: "I believe this behavior would be documented in the chipset data sheet rather than the SDM, since the chipset returns all 1s for an unclaimed read."] Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>		2017-03-09 15:34:51 +01:00
..
assigned-dev.c
assigned-dev.h
cpuid.c	sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>	2017-03-02 08:42:39 +01:00
cpuid.h
debugfs.c
emulate.c	Merge branch 'x86/cpufeature' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next	2017-01-17 17:53:01 +01:00
hyperv.c	sched/headers: Prepare to move cputime functionality from <linux/sched.h> into <linux/sched/cputime.h>	2017-03-02 08:42:39 +01:00
hyperv.h
i8254.c	KVM: x86: Handle the kthread worker using the new API	2016-12-08 15:31:11 +01:00
i8254.h	KVM: x86: Handle the kthread worker using the new API	2016-12-08 15:31:11 +01:00
i8259.c	KVM: x86: make pic setup code look like ioapic setup	2017-01-09 14:45:28 +01:00
ioapic.c	KVM: x86: fix out-of-bounds accesses of rtc_eoi map	2016-11-24 18:37:19 +01:00
ioapic.h	KVM: x86: fix out-of-bounds accesses of rtc_eoi map	2016-11-24 18:37:19 +01:00
iommu.c
irq_comm.c	sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h>	2017-03-02 08:42:38 +01:00
irq.c
irq.h	KVM: x86: make pic setup code look like ioapic setup	2017-01-09 14:45:28 +01:00
Kconfig
kvm_cache_regs.h
lapic.c	KVM: Support vCPU-based gfn->hva cache	2017-02-16 18:42:46 +01:00
lapic.h	KVM: x86: preparatory changes for APICv cleanups	2017-02-15 14:54:34 +01:00
Makefile
mmu_audit.c
mmu.c	sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>	2017-03-02 08:42:29 +01:00
mmu.h
mmutrace.h
mtrr.c
page_track.c	sched/headers: Prepare to use <linux/rcuupdate.h> instead of <linux/rculist.h> in <linux/sched.h>	2017-03-02 08:42:38 +01:00
paging_tmpl.h
pmu_amd.c
pmu_intel.c
pmu.c	KVM: x86: never specify a sample period for virtualized in_tx_cp counters	2017-03-01 14:19:46 +01:00
pmu.h
svm.c	KVM: x86: remove code for lazy FPU handling	2017-02-17 12:28:01 +01:00
trace.h
tss.h
vmx.c	KVM: nVMX: do not warn when MSR bitmap address is not backed	2017-03-09 15:34:51 +01:00
x86.c	sched/headers: Prepare to move sched_info_on() and force_schedstat_enabled() from <linux/sched.h> to <linux/sched/stat.h>	2017-03-02 08:42:39 +01:00
x86.h