Excerpts from Christian Zigotzky's message of June 12, 2020 11:01 pm: > On 11 June 2020 at 04:47 pm, Christian Zigotzky wrote: >> On 10 June 2020 at 01:23 pm, Christian Zigotzky wrote: >>> On 10 June 2020 at 11:06 am, Christian Zigotzky wrote: >>>> On 10 June 2020 at 00:18 am, Christian Zigotzky wrote: >>>>> Hello, >>>>> >>>>> KVM-PR doesn't work anymore on my Nemo board [1]. I figured out >>>>> that the Git kernels and the kernel 5.7 are affected. >>>>> >>>>> Error message: Fienix kernel: kvmppc_exit_pr_progint: emulation at >>>>> 700 failed (00000000) >>>>> >>>>> I can boot virtual QEMU PowerPC machines with KVM-PR with the >>>>> kernel 5.6 without any problems on my Nemo board. >>>>> >>>>> I tested it with QEMU 2.5.0 and QEMU 5.0.0 today. >>>>> >>>>> Could you please check KVM-PR on your PowerPC machine? >>>>> >>>>> Thanks, >>>>> Christian >>>>> >>>>> [1] https://en.wikipedia.org/wiki/AmigaOne_X1000 >>>> >>>> I figured out that the PowerPC updates 5.7-1 [1] are responsible for >>>> the KVM-PR issue. Please test KVM-PR on your PowerPC machines and >>>> check the PowerPC updates 5.7-1 [1]. >>>> >>>> Thanks >>>> >>>> [1] >>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d38c07afc356ddebaa3ed8ecb3f553340e05c969 >>>> >>>> >>> I tested the latest Git kernel with Mac-on-Linux/KVM-PR today. >>> Unfortunately I can't use KVM-PR with MoL anymore because of this >>> issue (see screenshots [1]). Please check the PowerPC updates 5.7-1. >>> >>> Thanks >>> >>> [1] >>> - >>> https://i.pinimg.com/originals/0c/b3/64/0cb364a40241fa2b7f297d4272bbb8b7.png >>> - >>> https://i.pinimg.com/originals/9a/61/d1/9a61d170b1c9f514f7a78a3014ffd18f.png >>> >> Hi All, >> >> I bisected today because of the KVM-PR issue. >> >> Result: >> >> 9600f261acaaabd476d7833cec2dd20f2919f1a0 is the first bad commit >> commit 9600f261acaaabd476d7833cec2dd20f2919f1a0 >> Author: Nicholas Piggin <npiggin@xxxxxxxxx> >> Date: Wed Feb 26 03:35:21 2020 +1000 >> >> powerpc/64s/exception: Move KVM test to common code >> >> This allows more code to be moved out of unrelocated regions. The >> system call KVMTEST is changed to be open-coded and remain in the >> tramp area to avoid having to move it to entry_64.S. The custom >> nature >> of the system call entry code means the hcall case can be made more >> streamlined than regular interrupt handlers. >> >> mpe: Incorporate fix from Nick: >> >> Moving KVM test to the common entry code missed the case of HMI and >> MCE, which do not do __GEN_COMMON_ENTRY (because they don't want to >> switch to virt mode). >> >> This means a MCE or HMI exception that is taken while KVM is >> running a >> guest context will not be switched out of that context, and KVM won't >> be notified. Found by running sigfuz in guest with patched host on >> POWER9 DD2.3, which causes some TM related HMI interrupts (which are >> expected and supposed to be handled by KVM). >> >> This fix adds a __GEN_REALMODE_COMMON_ENTRY for those handlers to add >> the KVM test. This makes them look a little more like other handlers >> that all use __GEN_COMMON_ENTRY. >> >> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx> >> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> >> Link: >> https://lore.kernel.org/r/20200225173541.1549955-13-npiggin@xxxxxxxxx >> >> :040000 040000 ec21cec22d165f8696d69532734cb2985d532cb0 >> 87dd49a9cd7202ec79350e8ca26cea01f1dbd93d M arch >> >> ----- >> >> The following commit is the problem: powerpc/64s/exception: Move KVM >> test to common code [1] >> >> These changes were included in the PowerPC updates 5.7-1. [2] >> >> Another test: >> >> git checkout d38c07afc356ddebaa3ed8ecb3f553340e05c969 (PowerPC updates >> 5.7-1 [2] ) -> KVM-PR doesn't work. >> >> After that: git revert d38c07afc356ddebaa3ed8ecb3f553340e05c969 -m 1 >> -> KVM-PR works. >> >> Could you please check the first bad commit? [1] >> >> Thanks, >> Christian >> >> >> [1] >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9600f261acaaabd476d7833cec2dd20f2919f1a0 >> [2] >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d38c07afc356ddebaa3ed8ecb3f553340e05c969 > > Hi All, > > I tried to revert the __GEN_REALMODE_COMMON_ENTRY fix for the latest Git > kernel and for the stable kernel 5.7.2 but without any success. There > was lot of restructuring work during the kernel 5.7 development time in > the PowerPC area so it isn't possible reactivate the old code. That > means we have lost the whole KVM-PR support. I also reported this issue > to Alexander Graf two days ago. He wrote: "Howdy :). It looks pretty > broken. Have you ever made a bisect to see where the problem comes from?" > > Please check the KVM-PR code. Does this patch fix it for you? The CTR register reload in the KVM interrupt path used the wrong save area for SLB (and NMI) interrupts. Fixes: 9600f261acaaa ("powerpc/64s/exception: Move KVM test to common code") Reported-by: Christian Zigotzky <chzigotzky@xxxxxxxxxxx> Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx> --- arch/powerpc/kernel/exceptions-64s.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index e70ebb5c318c..fa080694e581 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -270,7 +270,7 @@ BEGIN_FTR_SECTION END_FTR_SECTION_IFSET(CPU_FTR_CFAR) .endif - ld r10,PACA_EXGEN+EX_CTR(r13) + ld r10,IAREA+EX_CTR(r13) mtctr r10 BEGIN_FTR_SECTION ld r10,IAREA+EX_PPR(r13) @@ -298,7 +298,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) .if IKVM_SKIP 89: mtocrf 0x80,r9 - ld r10,PACA_EXGEN+EX_CTR(r13) + ld r10,IAREA+EX_CTR(r13) mtctr r10 ld r9,IAREA+EX_R9(r13) ld r10,IAREA+EX_R10(r13) -- 2.23.0
