Sean Christopherson 0aa1837533 KVM: x86: Properly reset MMU context at vCPU RESET/INIT ... Reset the MMU context at vCPU INIT (and RESET for good measure) if CR0.PG was set prior to INIT. Simply re-initializing the current MMU is not sufficient as the current root HPA may not be usable in the new context. E.g. if TDP is disabled and INIT arrives while the vCPU is in long mode, KVM will fail to switch to the 32-bit pae_root and bomb on the next VM-Enter due to running with a 64-bit CR3 in 32-bit mode. This bug was papered over in both VMX and SVM, but still managed to rear its head in the MMU role on VMX. Because EFER.LMA=1 requires CR0.PG=1, kvm_calc_shadow_mmu_root_page_role() checks for EFER.LMA without first checking CR0.PG. VMX's RESET/INIT flow writes CR0 before EFER, and so an INIT with the vCPU in 64-bit mode will cause the hack-a-fix to generate the wrong MMU role. In VMX, the INIT issue is specific to running without unrestricted guest since unrestricted guest is available if and only if EPT is enabled. Commit 8668a3c468 ("KVM: VMX: Reset mmu context when entering real mode") resolved the issue by forcing a reset when entering emulated real mode. In SVM, commit ebae871a50 ("kvm: svm: reset mmu on VCPU reset") forced a MMU reset on every INIT to workaround the flaw in common x86. Note, at the time the bug was fixed, the SVM problem was exacerbated by a complete lack of a CR4 update. The vendor resets will be reverted in future patches, primarily to aid bisection in case there are non-INIT flows that rely on the existing VMX logic. Because CR0.PG is unconditionally cleared on INIT, and because CR0.WP and all CR4/EFER paging bits are ignored if CR0.PG=0, simply checking that CR0.PG was '1' prior to INIT/RESET is sufficient to detect a required MMU context reset. Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210622175739.3610207-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2021-06-24 18:00:35 -04:00
..
boot	x86/boot/compressed: Enable -Wundef	2021-05-12 21:39:56 +02:00
configs	module: remove EXPORT_UNUSED_SYMBOL*	2021-02-08 12:28:07 +01:00
crypto	Objtool updates in this cycle were:	2021-04-28 12:53:24 -07:00
entry	Add Landlock, a new LSM from Mickaël Salaün <mic@linux.microsoft.com>	2021-05-01 18:50:44 -07:00
events	Handle power-gating of AMD IOMMU perf counters properly when they are used.	2021-05-09 13:00:26 -07:00
hyperv	The x86 MM changes in this cycle were:	2021-04-29 11:41:43 -07:00
ia32	x86/ia32_signal: Propagate __user annotation properly	2020-12-11 19:44:31 +01:00
include	KVM: stats: Separate generic stats from architecture specific ones	2021-06-24 11:47:56 -04:00
kernel	Merge branch 'topic/ppc-kvm' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into HEAD	2021-06-23 07:30:41 -04:00
kvm	KVM: x86: Properly reset MMU context at vCPU RESET/INIT	2021-06-24 18:00:35 -04:00
lib	- turn the stack canary into a normal __percpu variable on 32-bit which	2021-04-27 17:45:09 -07:00
math-emu	x86/fpu/math-emu: Fix function cast warning	2021-03-23 00:08:02 +01:00
mm	x86/msr: Rename MSR_K8_SYSCFG to MSR_AMD64_SYSCFG	2021-05-10 07:51:38 +02:00
net	Networking changes for 5.13.	2021-04-29 11:57:23 -07:00
pci	x86/msr: Rename MSR_K8_SYSCFG to MSR_AMD64_SYSCFG	2021-05-10 07:51:38 +02:00
platform	x86/sev-es: Rename sev-es.{ch} to sev.{ch}	2021-05-10 07:40:27 +02:00
power	- turn the stack canary into a normal __percpu variable on 32-bit which	2021-04-27 17:45:09 -07:00
purgatory	crypto: sha - split sha.h into sha1.h and sha2.h	2020-11-20 14:45:33 +11:00
ras
realmode	x86/msr: Rename MSR_K8_SYSCFG to MSR_AMD64_SYSCFG	2021-05-10 07:51:38 +02:00
tools	x86/tools/insn_sanity: Convert to insn_decode()	2021-03-15 12:21:11 +01:00
um	um: elf.h: Fix W=1 warning for empty body in 'do' statement	2021-04-15 23:10:50 +02:00
video
xen	Merge branch 'stable/for-linus-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb	2021-05-04 10:58:49 -07:00
.gitignore
Kbuild
Kconfig	x86/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE	2021-05-05 11:27:27 -07:00
Kconfig.assembler
Kconfig.cpu
Kconfig.debug	x86, libnvdimm/test: Remove COPY_MC_TEST	2020-10-26 18:08:35 +01:00
Makefile	Kbuild updates for v5.13	2021-04-29 14:24:39 -07:00
Makefile_32.cpu
Makefile.um