On 23/12/24 16:37, Paolo Bonzini wrote:
On Mon, Dec 23, 2024 at 3:41 PM Christian Zigotzky
<chzigot...@xenosoft.de> wrote:
Bisecting: a merge base must be tested
[e9001a382fa2c256229adc68d55212028b01d515] Merge tag
'kvmarm-fixes-6.12-3' of
git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
The host system doesn't boot.
Unfortunately, there isn't a guest kernel boot log via serial log.
No big deal since the boot hang was fixed via rebase.
git checkout -b bisection-rebase
b467ab82a9fde4b46c0cd2c299220857afb0e0d4
git rebase v6.12
The host kernel boots but the guest kernel doesn't boot so KVM HV
doesn't work.
As expected, so that's good.
git bisect start
git bisect bad bisection-rebase
git bisect good v6.12
[skipping bisection process]
`edebc0a1b7ab5ff19b4f5cd011c93196fc34b3e4 is the first bad commit
Ok, that means that the culprit is commit 419cfb983ca93 (the above
is the rebased hash). Thank you very much, your work was really
helpful!
Can you test this simple patch?
--------------- 8< ----------------
From: Paolo Bonzini <pbonz...@redhat.com>
Subject: [PATCH] KVM: allow NULL writable argument to __kvm_faultin_pfn
kvm_follow_pfn() is able to work with NULL in the .map_writable field
of the homonymous struct. But __kvm_faultin_pfn() rejects the combo
despite KVM for e500 trying to use it. Indeed .map_writable is not
particularly useful if the flags include FOLL_WRITE and readonly
guest memory is not supported, so add support to __kvm_faultin_pfn()
for this case.
Fixes: 1c7b627e9306 ("KVM: Add kvm_faultin_pfn() to specifically
service guest page faults")
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index de2c11dae231..5177e56fdbd5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2975,10 +2975,11 @@ kvm_pfn_t __kvm_faultin_pfn(const struct
kvm_memory_slot *slot, gfn_t gfn,
.refcounted_page = refcounted_page,
};
- if (WARN_ON_ONCE(!writable || !refcounted_page))
+ if (WARN_ON_ONCE(!refcounted_page))
return KVM_PFN_ERR_FAULT;
- *writable = false;
+ if (writable)
+ *writable = false;
*refcounted_page = NULL;
return kvm_follow_pfn(&kfp);
Thanks,
Paolo
Hello Paolo,
Thanks a lot for your patch.
I tested it with the RC4 of kernel 6.13 today but unfortunately it
doesn't solve the KVM HV issue. The guest system doesn't boot and I
can't see any error messages. (console=ttyS0)
Regards,
Christian
--
Sent with BrassMonkey 33.4.0
(https://github.com/wicknix/brass-monkey/releases/tag/33.4.0)
