KVM: x86: Rate-limit global clock updates on vCPU load

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commit 446fcce2a5 ("Revert "x86: kvm: rate-limit global clock updates"")
dropped the rate limiting for KVM_REQ_GLOBAL_CLOCK_UPDATE.

As a result, kvm_arch_vcpu_load() can queue global clock update requests
every time a vCPU is scheduled when the master clock is disabled or when
the vCPU is loaded for the first time.

Restore the throttling with a per-VM ratelimit state and gate
KVM_REQ_GLOBAL_CLOCK_UPDATE through __ratelimit(), so frequent vCPU
scheduling does not generate a steady stream of redundant clock update
requests.

Fixes: 446fcce2a5 ("Revert "x86: kvm: rate-limit global clock updates"")
Signed-off-by: Lei Chen <lei.chen@smartx.com>
Reported-by: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Closes: https://lore.kernel.org/all/CAK8fFZ5gY8_Mw2A=iZVFNVKQNrXQzVsn-HTd+Me9K6ZfmdgA+Q@mail.gmail.com/
Link: https://patch.msgid.link/20260409142226.2581-1-lei.chen@smartx.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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This commit is contained in:

Lei Chen 2026-04-09 22:22:26 +08:00 • committed by Sean Christopherson

parent fff82ea9d9

commit 8fe2e698fc

2 changed files with 10 additions and 2 deletions

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arch/x86/include/asm/kvm_host.h

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11

arch/x86/kvm/x86.c

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