From: Nicholas Piggin npiggin@gmail.com
commit cd81acc600a9684ea4b4d25a47900d38a3890eab upstream.
Commit 2284ffea8f0c ("powerpc/64s/exception: Only test KVM in SRR interrupts when PR KVM is supported") removed KVM guest tests from interrupts that do not set HV=1, when PR-KVM is not configured.
This is wrong for HV-KVM HPT guest MMIO emulation case which attempts to load the faulting instruction word with MSR[DR]=1 and MSR[HV]=1 with the guest MMU context loaded. This can cause host DSI, DSLB interrupts which must test for KVM guest. Restore this and add a comment.
Fixes: 2284ffea8f0c ("powerpc/64s/exception: Only test KVM in SRR interrupts when PR KVM is supported") Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20201117135617.3521127-1-npiggin@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/powerpc/kernel/exceptions-64s.S | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1410,6 +1410,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) * If none is found, do a Linux page fault. Linux page faults can happen in * kernel mode due to user copy operations of course. * + * KVM: The KVM HDSI handler may perform a load with MSR[DR]=1 in guest + * MMU context, which may cause a DSI in the host, which must go to the + * KVM handler. MSR[IR] is not enabled, so the real-mode handler will + * always be used regardless of AIL setting. + * * - Radix MMU * The hardware loads from the Linux page table directly, so a fault goes * immediately to Linux page fault. @@ -1420,10 +1425,8 @@ INT_DEFINE_BEGIN(data_access) IVEC=0x300 IDAR=1 IDSISR=1 -#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE IKVM_SKIP=1 IKVM_REAL=1 -#endif INT_DEFINE_END(data_access)
EXC_REAL_BEGIN(data_access, 0x300, 0x80) @@ -1462,6 +1465,8 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TY * ppc64_bolted_size (first segment). The kernel handler must avoid stomping * on user-handler data structures. * + * KVM: Same as 0x300, DSLB must test for KVM guest. + * * A dedicated save area EXSLB is used (XXX: but it actually need not be * these days, we could use EXGEN). */ @@ -1470,10 +1475,8 @@ INT_DEFINE_BEGIN(data_access_slb) IAREA=PACA_EXSLB IRECONCILE=0 IDAR=1 -#ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE IKVM_SKIP=1 IKVM_REAL=1 -#endif INT_DEFINE_END(data_access_slb)
EXC_REAL_BEGIN(data_access_slb, 0x380, 0x80)