s390/sthyi: add cache to store hypervisor info (9fb6c9b3) · Commits · 戴 / test

arch/s390/include/asm/kvm_host.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -736,7 +736,6 @@ struct kvm_arch{
		wait_queue_head_t ipte_wq;
		int ipte_lock_count;
		struct mutex ipte_mutex;
		struct ratelimit_state sthyi_limit;
		spinlock_t start_stop_lock;
		struct sie_page2 *sie_page2;
		struct kvm_s390_cpu_model model;

arch/s390/kernel/sthyi.c

+71 −13

Original line number	Diff line number	Diff line
		@@ -11,7 +11,6 @@
		#include <linux/errno.h>
		#include <linux/pagemap.h>
		#include <linux/vmalloc.h>
		#include <linux/ratelimit.h>

		#include <asm/asm-offsets.h>
		#include <asm/sclp.h>
		@@ -139,6 +138,21 @@ struct lpar_cpu_inf {
		struct cpu_inf ifl;
		};

		/*
		* STHYI requires extensive locking in the higher hypervisors
		* and is very computational/memory expensive. Therefore we
		* cache the retrieved data whose valid period is 1s.
		*/
		#define CACHE_VALID_JIFFIES HZ

		struct sthyi_info {
		void *info;
		unsigned long end;
		};

		static DEFINE_MUTEX(sthyi_mutex);
		static struct sthyi_info sthyi_cache;

		static inline u64 cpu_id(u8 ctidx, void *diag224_buf)
		{
		return ((u64 )(diag224_buf + (ctidx + 1) * DIAG204_CPU_NAME_LEN));
		@@ -395,6 +409,47 @@ static int sthyi(u64 vaddr, u64 *rc)
		return cc;
		}

		static int fill_dst(void dst, u64 rc)
		{
		struct sthyi_sctns sctns = (struct sthyi_sctns )dst;

		/*
		* If the facility is on, we don't want to emulate the instruction.
		* We ask the hypervisor to provide the data.
		*/
		if (test_facility(74))
		return sthyi((u64)dst, rc);

		fill_hdr(sctns);
		fill_stsi(sctns);
		fill_diag(sctns);
		*rc = 0;
		return 0;
		}

		static int sthyi_init_cache(void)
		{
		if (sthyi_cache.info)
		return 0;
		sthyi_cache.info = (void *)get_zeroed_page(GFP_KERNEL);
		if (!sthyi_cache.info)
		return -ENOMEM;
		sthyi_cache.end = jiffies - 1; /* expired */
		return 0;
		}

		static int sthyi_update_cache(u64 *rc)
		{
		int r;

		memset(sthyi_cache.info, 0, PAGE_SIZE);
		r = fill_dst(sthyi_cache.info, rc);
		if (r)
		return r;
		sthyi_cache.end = jiffies + CACHE_VALID_JIFFIES;
		return r;
		}

		/*
		* sthyi_fill - Fill page with data returned by the STHYI instruction
		*
		@@ -409,20 +464,23 @@ static int sthyi(u64 vaddr, u64 *rc)
		*/
		int sthyi_fill(void dst, u64 rc)
		{
		struct sthyi_sctns sctns = (struct sthyi_sctns )dst;
		int r;

		/*
		* If the facility is on, we don't want to emulate the instruction.
		* We ask the hypervisor to provide the data.
		*/
		if (test_facility(74))
		return sthyi((u64)dst, rc);

		fill_hdr(sctns);
		fill_stsi(sctns);
		fill_diag(sctns);
		mutex_lock(&sthyi_mutex);
		r = sthyi_init_cache();
		if (r)
		goto out;

		if (time_is_before_jiffies(sthyi_cache.end)) {
		/* cache expired */
		r = sthyi_update_cache(rc);
		if (r)
		goto out;
		}
		*rc = 0;
		return 0;
		memcpy(dst, sthyi_cache.info, PAGE_SIZE);
		out:
		mutex_unlock(&sthyi_mutex);
		return r;
		}
		EXPORT_SYMBOL_GPL(sthyi_fill);

arch/s390/kvm/intercept.c

+0 −10

Original line number	Diff line number	Diff line
		@@ -375,16 +375,6 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
		if (!test_kvm_facility(vcpu->kvm, 74))
		return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);

		/*
		* STHYI requires extensive locking in the higher hypervisors
		* and is very computational/memory expensive. Therefore we
		* ratelimit the executions per VM.
		*/
		if (!__ratelimit(&vcpu->kvm->arch.sthyi_limit)) {
		kvm_s390_retry_instr(vcpu);
		return 0;
		}

		kvm_s390_get_regs_rre(vcpu, &reg1, &reg2);
		code = vcpu->run->s.regs.gprs[reg1];
		addr = vcpu->run->s.regs.gprs[reg2];

arch/s390/kvm/kvm-s390.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -1884,8 +1884,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)

		rc = -ENOMEM;

		ratelimit_state_init(&kvm->arch.sthyi_limit, 5 * HZ, 500);

		kvm->arch.use_esca = 0; /* start with basic SCA */
		if (!sclp.has_64bscao)
		alloc_flags \|= GFP_DMA;

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