Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") made it possible to observe VP_INVAL returned from
hv_cpu_number_to_vp_number() and cpumask_to_vpset() and PV TLB flush
code needs to be adjusted.
The window when VP_INVAL is observable is very short, I'm not even sure
we do TLB flushes during this period (secodary CPUs bringup on boot, there
is no CPU hotplug on Hyper-V yet). This, however, may change in future so
let's fix this now.
Thomas, Ingo: these patches are for 'tip/x86/hyperv'. I don't think we have
a real issue in 4.18 but I can definitely prepare fixes for it if you think
this is needed.
Vitaly Kuznetsov (2):
x86/hyper-v: check cpumask_to_vpset() return value in
hyperv_flush_tlb_others_ex()
x86/hyper-v: check for VP_INVAL in hyperv_flush_tlb_others()
arch/x86/hyperv/mmu.c | 7 +++++++
1 file changed, 7 insertions(+)
--
2.14.4
Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") made cpumask_to_vpset() return '-1' when there is a CPU
with unknown VP index in the supplied set. This needs to be checked before
we pass 'nr_bank' to hypercall.
Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <[email protected]>
---
arch/x86/hyperv/mmu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 0d90e515ec98..453d2355cd61 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -186,6 +186,8 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
nr_bank = cpumask_to_vpset(&(flush->hv_vp_set), cpus);
+ if (nr_bank < 0)
+ return U64_MAX;
/*
* We can flush not more than max_gvas with one hypercall. Flush the
--
2.14.4
Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") pre-filled hv_vp_index with VP_INVAL so it is now
(theoretically) possible to observe hv_cpu_number_to_vp_number()
returning VP_INVAL. We need to check for that in hyperv_flush_tlb_others().
Not checking for VP_INVAL on the first call site where we do
if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
goto do_ex_hypercall;
is OK, in case we're eligible for non-ex hypercall we'll catch the
issue later in for_each_cpu() cycle and in case we'll be doing ex-
hypercall cpumask_to_vpset() will fail.
It would be nice to change hv_cpu_number_to_vp_number() return
value's type to 'u32' but this will likely be a bigger change as
all call sites need to be checked first.
Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <[email protected]>
---
arch/x86/hyperv/mmu.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 453d2355cd61..1147e1fed7ff 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -111,6 +111,11 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
for_each_cpu(cpu, cpus) {
vcpu = hv_cpu_number_to_vp_number(cpu);
+ if (vcpu == VP_INVAL) {
+ local_irq_restore(flags);
+ goto do_native;
+ }
+
if (vcpu >= 64)
goto do_ex_hypercall;
--
2.14.4
From: Vitaly Kuznetsov <[email protected]> Monday, July 9, 2018 10:40 AM
> Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
> enlightenment") made cpumask_to_vpset() return '-1' when there is a CPU
> with unknown VP index in the supplied set. This needs to be checked before
> we pass 'nr_bank' to hypercall.
>
> Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
> Signed-off-by: Vitaly Kuznetsov <[email protected]>
> ---
> arch/x86/hyperv/mmu.c | 2 ++
> 1 file changed, 2 insertions(+)
Reviewed-by: Michael Kelley <[email protected]>
From: Vitaly Kuznetsov <[email protected]> Monday, July 9, 2018 10:40 AM
> Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
> enlightenment") pre-filled hv_vp_index with VP_INVAL so it is now
> (theoretically) possible to observe hv_cpu_number_to_vp_number()
> returning VP_INVAL. We need to check for that in hyperv_flush_tlb_others().
>
> Not checking for VP_INVAL on the first call site where we do
>
> if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
> goto do_ex_hypercall;
>
> is OK, in case we're eligible for non-ex hypercall we'll catch the
> issue later in for_each_cpu() cycle and in case we'll be doing ex-
> hypercall cpumask_to_vpset() will fail.
>
> It would be nice to change hv_cpu_number_to_vp_number() return
> value's type to 'u32' but this will likely be a bigger change as
> all call sites need to be checked first.
>
> Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
> Signed-off-by: Vitaly Kuznetsov <[email protected]>
> ---
> arch/x86/hyperv/mmu.c | 5 +++++
> 1 file changed, 5 insertions(+)
Reviewed-by: Michael Kelley <[email protected]>
Commit-ID: 110d2a7fc39725d2c29d2fede4f34a35a4f98882
Gitweb: https://git.kernel.org/tip/110d2a7fc39725d2c29d2fede4f34a35a4f98882
Author: Vitaly Kuznetsov <[email protected]>
AuthorDate: Mon, 9 Jul 2018 19:40:12 +0200
Committer: Thomas Gleixner <[email protected]>
CommitDate: Mon, 16 Jul 2018 11:19:49 +0200
x86/hyper-v: Check for VP_INVAL in hyperv_flush_tlb_others()
Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") pre-filled hv_vp_index with VP_INVAL so it is now
(theoretically) possible to observe hv_cpu_number_to_vp_number()
returning VP_INVAL. We need to check for that in hyperv_flush_tlb_others().
Not checking for VP_INVAL on the first call site where we do
if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
goto do_ex_hypercall;
is OK, in case we're eligible for non-ex hypercall we'll catch the
issue later in for_each_cpu() cycle and in case we'll be doing ex-
hypercall cpumask_to_vpset() will fail.
It would be nice to change hv_cpu_number_to_vp_number() return
value's type to 'u32' but this will likely be a bigger change as
all call sites need to be checked first.
Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: "Michael Kelley (EOSG)" <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/hyperv/mmu.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 453d2355cd61..1147e1fed7ff 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -111,6 +111,11 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
for_each_cpu(cpu, cpus) {
vcpu = hv_cpu_number_to_vp_number(cpu);
+ if (vcpu == VP_INVAL) {
+ local_irq_restore(flags);
+ goto do_native;
+ }
+
if (vcpu >= 64)
goto do_ex_hypercall;
Commit-ID: 0f0caa52cd4a48a44f6cdc77bf83272bbb450727
Gitweb: https://git.kernel.org/tip/0f0caa52cd4a48a44f6cdc77bf83272bbb450727
Author: Vitaly Kuznetsov <[email protected]>
AuthorDate: Mon, 9 Jul 2018 19:40:11 +0200
Committer: Thomas Gleixner <[email protected]>
CommitDate: Mon, 16 Jul 2018 11:19:48 +0200
x86/hyper-v: Check cpumask_to_vpset() return value in hyperv_flush_tlb_others_ex()
Commit 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI
enlightenment") made cpumask_to_vpset() return '-1' when there is a CPU
with unknown VP index in the supplied set. This needs to be checked before
we pass 'nr_bank' to hypercall.
Fixes: 1268ed0c474a ("x86/hyper-v: Fix the circular dependency in IPI enlightenment")
Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: "Michael Kelley (EOSG)" <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/hyperv/mmu.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 0d90e515ec98..453d2355cd61 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -186,6 +186,8 @@ static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
nr_bank = cpumask_to_vpset(&(flush->hv_vp_set), cpus);
+ if (nr_bank < 0)
+ return U64_MAX;
/*
* We can flush not more than max_gvas with one hypercall. Flush the