KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Cc: stable@vger.kernel.org
Reported-by: Stefan Teodorescu <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 263 insertions, 0 deletions

diff --git a/drivers/clk/sprd/pll.c b/drivers/clk/sprd/pll.c
new file mode 100644
index 000000000..4aec30777
--- /dev/null
+++ b/drivers/clk/sprd/pll.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Spreadtrum pll clock driver
+//
+// Copyright (C) 2015~2017 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "pll.h"
+
+#define CLK_PLL_1M	1000000
+#define CLK_PLL_10M	(CLK_PLL_1M * 10)
+
+#define pindex(pll, member)		\
+	(pll->factors[member].shift / (8 * sizeof(pll->regs_num)))
+
+#define pshift(pll, member)		\
+	(pll->factors[member].shift % (8 * sizeof(pll->regs_num)))
+
+#define pwidth(pll, member)		\
+	pll->factors[member].width
+
+#define pmask(pll, member)					\
+	((pwidth(pll, member)) ?				\
+	GENMASK(pwidth(pll, member) + pshift(pll, member) - 1,	\
+	pshift(pll, member)) : 0)
+
+#define pinternal(pll, cfg, member)	\
+	(cfg[pindex(pll, member)] & pmask(pll, member))
+
+#define pinternal_val(pll, cfg, member)	\
+	(pinternal(pll, cfg, member) >> pshift(pll, member))
+
+static inline unsigned int
+sprd_pll_read(const struct sprd_pll *pll, u8 index)
+{
+	const struct sprd_clk_common *common = &pll->common;
+	unsigned int val = 0;
+
+	if (WARN_ON(index >= pll->regs_num))
+		return 0;
+
+	regmap_read(common->regmap, common->reg + index * 4, &val);
+
+	return val;
+}
+
+static inline void
+sprd_pll_write(const struct sprd_pll *pll, u8 index,
+				  u32 msk, u32 val)
+{
+	const struct sprd_clk_common *common = &pll->common;
+	unsigned int offset, reg;
+	int ret = 0;
+
+	if (WARN_ON(index >= pll->regs_num))
+		return;
+
+	offset = common->reg + index * 4;
+	ret = regmap_read(common->regmap, offset, &reg);
+	if (!ret)
+		regmap_write(common->regmap, offset, (reg & ~msk) | val);
+}
+
+static unsigned long pll_get_refin(const struct sprd_pll *pll)
+{
+	u32 shift, mask, index, refin_id = 3;
+	const unsigned long refin[4] = { 2, 4, 13, 26 };
+
+	if (pwidth(pll, PLL_REFIN)) {
+		index = pindex(pll, PLL_REFIN);
+		shift = pshift(pll, PLL_REFIN);
+		mask = pmask(pll, PLL_REFIN);
+		refin_id = (sprd_pll_read(pll, index) & mask) >> shift;
+		if (refin_id > 3)
+			refin_id = 3;
+	}
+
+	return refin[refin_id];
+}
+
+static u32 pll_get_ibias(u64 rate, const u64 *table)
+{
+	u32 i, num = table[0];
+
+	/* table[0] indicates the number of items in this table */
+	for (i = 0; i < num; i++)
+		if (rate <= table[i + 1])
+			break;
+
+	return i == num ? num - 1 : i;
+}
+
+static unsigned long _sprd_pll_recalc_rate(const struct sprd_pll *pll,
+					   unsigned long parent_rate)
+{
+	u32 *cfg;
+	u32 i, mask, regs_num = pll->regs_num;
+	unsigned long rate, nint, kint = 0;
+	u64 refin;
+	u16 k1, k2;
+
+	cfg = kcalloc(regs_num, sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return parent_rate;
+
+	for (i = 0; i < regs_num; i++)
+		cfg[i] = sprd_pll_read(pll, i);
+
+	refin = pll_get_refin(pll);
+
+	if (pinternal(pll, cfg, PLL_PREDIV))
+		refin = refin * 2;
+
+	if (pwidth(pll, PLL_POSTDIV) &&
+	    ((pll->fflag == 1 && pinternal(pll, cfg, PLL_POSTDIV)) ||
+	     (!pll->fflag && !pinternal(pll, cfg, PLL_POSTDIV))))
+		refin = refin / 2;
+
+	if (!pinternal(pll, cfg, PLL_DIV_S)) {
+		rate = refin * pinternal_val(pll, cfg, PLL_N) * CLK_PLL_10M;
+	} else {
+		nint = pinternal_val(pll, cfg, PLL_NINT);
+		if (pinternal(pll, cfg, PLL_SDM_EN))
+			kint = pinternal_val(pll, cfg, PLL_KINT);
+
+		mask = pmask(pll, PLL_KINT);
+
+		k1 = pll->k1;
+		k2 = pll->k2;
+		rate = DIV_ROUND_CLOSEST_ULL(refin * kint * k1,
+					 ((mask >> __ffs(mask)) + 1)) *
+					 k2 + refin * nint * CLK_PLL_1M;
+	}
+
+	kfree(cfg);
+	return rate;
+}
+
+#define SPRD_PLL_WRITE_CHECK(pll, i, mask, val)		\
+	(((sprd_pll_read(pll, i) & mask) == val) ? 0 : (-EFAULT))
+
+static int _sprd_pll_set_rate(const struct sprd_pll *pll,
+			      unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct reg_cfg *cfg;
+	int ret = 0;
+	u32 mask, shift, width, ibias_val, index;
+	u32 regs_num = pll->regs_num, i = 0;
+	unsigned long kint, nint;
+	u64 tmp, refin, fvco = rate;
+
+	cfg = kzalloc_objs(*cfg, regs_num);
+	if (!cfg)
+		return -ENOMEM;
+
+	refin = pll_get_refin(pll);
+
+	mask = pmask(pll, PLL_PREDIV);
+	index = pindex(pll, PLL_PREDIV);
+	width = pwidth(pll, PLL_PREDIV);
+	if (width && (sprd_pll_read(pll, index) & mask))
+		refin = refin * 2;
+
+	mask = pmask(pll, PLL_POSTDIV);
+	index = pindex(pll, PLL_POSTDIV);
+	width = pwidth(pll, PLL_POSTDIV);
+	cfg[index].msk = mask;
+	if (width && ((pll->fflag == 1 && fvco <= pll->fvco) ||
+		      (pll->fflag == 0 && fvco > pll->fvco)))
+		cfg[index].val |= mask;
+
+	if (width && fvco <= pll->fvco)
+		fvco = fvco * 2;
+
+	mask = pmask(pll, PLL_DIV_S);
+	index = pindex(pll, PLL_DIV_S);
+	cfg[index].val |= mask;
+	cfg[index].msk |= mask;
+
+	mask = pmask(pll, PLL_SDM_EN);
+	index = pindex(pll, PLL_SDM_EN);
+	cfg[index].val |= mask;
+	cfg[index].msk |= mask;
+
+	nint = do_div(fvco, refin * CLK_PLL_1M);
+	mask = pmask(pll, PLL_NINT);
+	index = pindex(pll, PLL_NINT);
+	shift = pshift(pll, PLL_NINT);
+	cfg[index].val |= (nint << shift) & mask;
+	cfg[index].msk |= mask;
+
+	mask = pmask(pll, PLL_KINT);
+	index = pindex(pll, PLL_KINT);
+	width = pwidth(pll, PLL_KINT);
+	shift = pshift(pll, PLL_KINT);
+	tmp = fvco - refin * nint * CLK_PLL_1M;
+	tmp = do_div(tmp, 10000) * ((mask >> shift) + 1);
+	kint = DIV_ROUND_CLOSEST_ULL(tmp, refin * 100);
+	cfg[index].val |= (kint << shift) & mask;
+	cfg[index].msk |= mask;
+
+	ibias_val = pll_get_ibias(fvco, pll->itable);
+
+	mask = pmask(pll, PLL_IBIAS);
+	index = pindex(pll, PLL_IBIAS);
+	shift = pshift(pll, PLL_IBIAS);
+	cfg[index].val |= ibias_val << shift & mask;
+	cfg[index].msk |= mask;
+
+	for (i = 0; i < regs_num; i++) {
+		if (cfg[i].msk) {
+			sprd_pll_write(pll, i, cfg[i].msk, cfg[i].val);
+			ret |= SPRD_PLL_WRITE_CHECK(pll, i, cfg[i].msk,
+						   cfg[i].val);
+		}
+	}
+
+	if (!ret)
+		udelay(pll->udelay);
+
+	kfree(cfg);
+	return ret;
+}
+
+static unsigned long sprd_pll_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct sprd_pll *pll = hw_to_sprd_pll(hw);
+
+	return _sprd_pll_recalc_rate(pll, parent_rate);
+}
+
+static int sprd_pll_set_rate(struct clk_hw *hw,
+			     unsigned long rate,
+			     unsigned long parent_rate)
+{
+	struct sprd_pll *pll = hw_to_sprd_pll(hw);
+
+	return _sprd_pll_set_rate(pll, rate, parent_rate);
+}
+
+static int sprd_pll_clk_prepare(struct clk_hw *hw)
+{
+	struct sprd_pll *pll = hw_to_sprd_pll(hw);
+
+	udelay(pll->udelay);
+
+	return 0;
+}
+
+const struct clk_ops sprd_pll_ops = {
+	.prepare = sprd_pll_clk_prepare,
+	.recalc_rate = sprd_pll_recalc_rate,
+	.determine_rate = clk_determine_rate_noop,
+	.set_rate = sprd_pll_set_rate,
+};
+EXPORT_SYMBOL_GPL(sprd_pll_ops);