66 lines
2.4 KiB
Diff
66 lines
2.4 KiB
Diff
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From ff43e9201aba8f4047e6fd5edb93a4861cc8fed2 Mon Sep 17 00:00:00 2001
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From: Yanan Wang <wangyanan55@huawei.com>
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Date: Thu, 28 Mar 2024 18:57:56 +0800
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Subject: [PATCH] i386: cache passthrough: Update AMD 8000_001D.EAX[25:14]
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based on vCPU topo
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On AMD target, when host cache passthrough is disabled we will
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emulate the guest caches with default values and initialize the
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shared cpu list of the caches based on vCPU topology. However
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when host cache passthrough is enabled, the shared cpu list is
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consistent with host regardless what the vCPU topology is.
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For example, when cache passthrough is enabled, running a guest
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with vThreads=1 on a host with pThreads=2, we will get that there
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are every *two* logical vCPUs sharing a L1/L2 cache, which is not
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consistent with the vCPU topology (vThreads=1).
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So let's reinitialize BITs[25:14] of AMD CPUID 8000_001D.EAX
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based on the actual vCPU topology instead of host pCPU topology.
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Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
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Signed-off-by: Yuan Zhang <zhangyuan162@huawei.com>
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---
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target/i386/cpu.c | 22 ++++++++++++++++++++++
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1 file changed, 22 insertions(+)
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diff --git a/target/i386/cpu.c b/target/i386/cpu.c
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index f94405c02b..491cf40cc7 100644
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--- a/target/i386/cpu.c
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+++ b/target/i386/cpu.c
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@@ -6597,9 +6597,31 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
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}
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break;
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case 0x8000001D:
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+ /* Populate AMD Processor Cache Information */
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*eax = 0;
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if (cpu->cache_info_passthrough) {
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x86_cpu_get_cache_cpuid(index, count, eax, ebx, ecx, edx);
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+
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+ /*
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+ * Clear BITs[25:14] and then update them based on the guest
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+ * vCPU topology, like what we do in encode_cache_cpuid8000001d
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+ * when cache_info_passthrough is not enabled.
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+ */
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+ *eax &= ~0x03FFC000;
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+ switch (count) {
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+ case 0: /* L1 dcache info */
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+ case 1: /* L1 icache info */
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+ case 2: /* L2 cache info */
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+ *eax |= ((topo_info.threads_per_core - 1) << 14);
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+ break;
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+ case 3: /* L3 cache info */
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+ *eax |= ((topo_info.cores_per_die *
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+ topo_info.threads_per_core - 1) << 14);
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+ break;
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+ default: /* end of info */
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+ *eax = *ebx = *ecx = *edx = 0;
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+ break;
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+ }
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break;
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}
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switch (count) {
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--
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2.27.0
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